That's so, so awesome that you have been able to connect with those parts and experience them as feeling real to you!
I can relate to the realness fading so that it feels "not real" again. We have done some IFS work but since making some major breakthroughs we have gone back to struggling a LOT with denial again. T has told me that my "default setting" is the unreality of it, that is what the dissociation was about. She said it makes perfect sense to her that I wouldn't suddenly just know everything was real. If that happened I would be completely overwhelmed with the reality of everything that happened. (That is what happened actually ... we had a massive breakthrough that was emotionally overwhelming for a week or two and we didn't cope well.... then we retreated back into denial). She said it is natural for the healing and acceptance to come in bits and for old coping mechanisms (dissociative denial) to ebb and flow.

I have been trying to be more accepting of that (T said it felt real to me before and it will again, my connection to it has just faded a bit for now) and it has helped. I know she is right, that it will definitely feel real again at some point!

Maybe you could think of it as "having a bit of a break".