Seems like standard behaviour for an INFJ who needs something, has tried all the non-drama-queen ways she knows of getting it, and has reached the end of her rope and is flailing desperately.
My guess would be that she doesn't necessarily need more of your time per sé (because what I know about myself and other INFJs is that they're happy to generously sacrifice their wants for the person they love, as long as they feel important), but that she's feeling unloved and alone because you have a bunch of small mannerisms that trigger loneliness. The time thing is just something that it's more or less reasonable to talk about, while the little mannerisms are harder to discuss or even identify. People would understand 'my boyfriend just ran away in the middle of a conversation!' as a plea for comfort, but would think 'my boyfriend always exhales audibly before responding to me if I say something!' as overblown. But can both have a strong effect on the health of your relationship. From my own experience, I don't mind if my husband is gone for 23 hours per day, as long as he makes me feel loved that one hour we do have.
(This theory is from the Gottman Institute. Awesome relationship research. Nice quick test to see how you're doing with your relationship at Bids For Connection Quiz
) She probably has a bunch of different ways in which she tells you she needs a small bit of your attention, and it's likely that you don't even recognize half of them. (This is because INFJs tend to be unreasonably subtle and INTJs tend to be rather oblivious in this respect.) So she bids for your attention and you turn away from her, maybe without even noticing that you are, in effect, saying 'you're not that important to me right now.' She's probably tried increasing the number of attempts to get your attention, only to discover that you still don't recognize some and likely even get annoyed and pressured by the increased requests. If so, you're still turning away from her at times, and now you might even be turning against her some other times, which probably sounds to her like not only is she still not that important, you dislike her trying to make herself important.
So what's an INFJ to do? She loves you, so she doesn't want to pressure you if it only makes you feel bad. She's also feeling lonely, and wants a higher percentage of her bids for connection to get a 'turn toward' response, which makes her feel loved and important. But increasing her bids hasn't helped. So all she can do is wait and hope YOU feel a little lonely and increase the number of your bids. In theory, that's a good plan - if YOU bid for HER attention, she has the power to respond favourably, increasing her feeling of love, while if she bids, whether it's going to result in success or loneliness is out of her hands.
However, INFJs are slightly clingy and INTJs are notorious Einzelgängers, so if she's waiting for you to miss her that's just never going to happen. Sure, eventually you'd turn toward her more, but you'll never need the frequency of positive interaction that she does.
Eventually, she ends up frazzled and loses all perspective and starts wars about who says what to whom on Twitter. This is NOT a healthy behaviour, but it's also not really useful to criticise it if you're not going to fix the underlying reasons she got that frazzled in the first place. She's probably feeling horrible about herself for acting that way and hopes that you won't hold it against her forever. (Heh, ask me how I know. Not proud of some of the things I did to get my (likely xSTJ) husband's attention.)
- learn about these bids. Gottman has a book. Might be worth a look.
- she needs to learn to be a little less subtle, so you notice her bids more and don't accidentally ignore her. It's possible to talk about these things directly. Or maybe give her that book.
If you ARE capable of discussing these things, it's interesting to find out which ways of 'turning away' she finds most painful and pay particular attention to not doing them.
- you need to learn to be a little more perceptive, for which I've found just being aware of the existence of 'bids for connection' helps a lot - and just to ease a potential worry, it's not the case that every bid for connection she does needs to be followed by half an hour of sickening romance. Tiny gestures like a smile or a nod or a touch or a 'can I get back to you? I'm in a crucial phase of something right now' help a lot. The theory says that happy couples can have something like 10 successful bids per minute, so each bid isn't supposed to take much longer than a few milliseconds.
- pro-tip: flood HER with bids, so she'll feel happy and not bid at you so much. This gives you a huge buffer to miss a few of her bids because they're too subtle or you're too focused on whatever you're doing. Other pluses: you can control when you bid and how you bid, and you bidding for HER attention scores you a lot more happyfuzzy points than you responding favourably to her bid for your attention. It's not hard to work out little gestures like smiles and touches that light her up, and it can be a fun and not very time-consuming game to get good at doing this.
[Edited to add:] You posted some situations in which it's necessary to retreat a bit. It's possible to say 'no I don't need you there' while still honouring her bid for connection with a 'turn toward' response. It's not going to be your default response, but you can learn it and make sure your I-need-to-be-alone requests get the answer of 'I understand, honey. You go do what you have to do. I love you, and will be right here when you come back.' A happy, fulfilled INFJ will probably love doing that for her SO. [End edit.]
[Edited to add:] Concerning the 'immaturity' of this INFJ: I think there's immaturity at play, but maybe not where you think it is. The fact that she needs more positive interactions than you to feel optimally happy and secure has nothing to do with being immature. That likely has to do just with personality. So you don't get to feel like the stable, mature one because you happen to be a little less mate-focused in your setup. Even the most loving, mature, stable INFJ will feel deeply unhappy when their needs aren't met for a long time. The difference is that a loving, mature, stable INFJ would probably do 2 things differently: a) She'd never let it get that far. She would've said much earlier "Look, there seems to be a difference in what we need from each other. What I need is X, and I'm going to make it easy for you to give that to me by being honest about what works best and give you feedback on how we're doing. Are you willing to learn how do that? It's important to me. If you're not, no hard feelings but then we are not the right people for each other." b) If it did happen to get that far accidentally, she'd have better self-soothing skills and problem-solving skills, and wouldn't lash out like that. And if things kept threatening to get that far, despite verbal assurances that her needs are important too, she'd know when to cut her losses. [End edit 2.]
It all depends on how much you want to invest in this relationship. This give-and-take dynamic is present in ALL relationships, but some people will be closer to your own native level of neediness. You both need a certain amount of openness and willingness to try stuff to be able to get good at this. She's also definitely going to need to create better signaling mechanisms than running away and posting her stress on a public forum.
Good luck to you both!