As far as INTP goes, it took me a long time to allow myself to feel emotion... and then to be able to identify the emotion... and then to be able to articulate nuanced emotion.
(One big block was just being able to admit I felt emotions like other people and that I couldn't avoid their influence in my perception and decision-making process... and it was okay, because that's part of being human and being alive.)
INFJ seems to me to be very vulnerable regarding their emotional state, but maybe it comes down to what was suggested ... they're not sure what is best/right/healthiest and thus unwilling to speak/label it? I don't know.
I agree with the INTJ thing, at least as the other end of an INTJ exchange: I usually feel that they grasp the ideas of what I'm saying, but I don't often get a vibe back that they understand (or at least validate) the emotional content... the emotional content often seems dismissed or set aside as irrelevant and not a factor... even with INTJs I find cordial. (And maybe that describes it best: INTJs can be cordial, which is how they typically seem to show concern/interest, but I don't particular find them warm as a group.)
It took me so many years to figure this out, but it's really what I go through.
Similarly, for many years I had an inability to say "no." If someone asked me to do something, I felt angry and overwhelmed because I now felt I had to do it; this is one reason why I avoided relationships for so long and felt I had to be alone in order to retain my autonomy. It always frustrated me to no end that I couldn't say "no" but I just couldn't. It grew particularly bad if the decision was one based more on preference and/or emotion; if I had a rational reason to say no, then it was easier for me... so I would construct elaborate reasons why I couldn't do what someone requested so that they would have no reason to be mad at me for saying no to their request. I felt like if I did not justify my decision, then I would have to deal with their negative emotion/opinion of me (which I didn't want to deal with), but also that if I could not rationally support my decision, then I had no reason to say no except to be a jerk or be mean.
Needless to say, this got me stuck in many situations I did not want to be in, and I would feel very unhappy. In the end, it was easier to avoid people.
Relationships of course were the epitome of trouble... but I became horrendously lonely if I avoided relationships. It was a real push/pull; I wanted to be known and accepted, but I couldn't afford for people to constantly step over my non-existent boundaries by being in a relationship. Even when I was in a relationship, I kept as much information about my feelings and desires hidden as possible, and tried to stay away from situations where someone might want me to do something, since I had no way to say no.
Even now, at my best... that's my biggest problem in my current relationship. I hate not being close to my partner, but the closer I get, the more smothered I can feel even if rationally I know he's oh so free in regards to letting me define my own boundaries. As soon as he gets too close for too long, I start distancing myself by nature; and the biggest issue has been his knowledge that he wants to be with me for always, where I know I love him but I'm uneasy about the commitment... it terrifies me for some reason. (It didn't help that I've been there and done that before, and it was a really hard relationship; I'm happy for how it changed me, but it hurt bad enough I don't want to do it again.)
Anyway, for some reason, e5 (esp the INTP blend) is traditionally withdrawn and observatory because the personal boundaries are so weak. Compare to the e8, which has very assertive and tough exterior boundaries, so e8 can charge into conflict and butt heads with anyone and overwhelm THEM rather than being overwhelmed. As e5 -> e8, it gains confidence and a sense of self and boundaries and can assert itself against others without being damaged by whoever e5 comes into contact with; it's no longer thin-skinned and delicate, it knows itself and can flex and protect itself without having to disengage.