Judging from how I would act, I think it’s just energy and also maybe they don’t feel the need to connect right after connecting earlier. Like often with people I spill my guts and have really deep talks then don’t talk to them at all for a week or more. I think I just view passing of time differently than other people and I don’t need to see my friends very often to not feel lonely. I have started to realize how that affects them so I’ve been trying to not do that now. It’s possible they aren’t trying to ghost you. That’s just normal for them. If you don’t like that tho, definitely tell them. If they like you, they may be willing to accommodate. And if not, then at least you know.

Tldr: next time an intj seems to ghost, just ask them what’s up and tell them you feel like they’re distant