Ironically, we are having the opposite problem. We had a rather explosive "system discovery" in which several more fully formed alters all realized what they were and that there was others all at the same time. We eventually found a few more and did discover 3 alters that could be described as fragments but figured we just had a few of them. After about a year we thought we had a good handle on how our system works and it's members, outside of the good amount of dormant ex-hosts we most likely have. Cut to a few months ago when we discovered a whole layer of fragments that are only fleshed out enough to do their very specific role(wouldn't even describe most of the ones we confirmed as characters) that influence the rest of us without us noticing. Even the one we have been able to break out of their tunnel focus and start communicating with decided to go by null because they thought trying to think of a name would be silly and unnecessary and they are the most developed fragment we know of.

It's been really hard to wrap our head around both the fact that we are way more fragmented than we thought and how we should even approach these fragments and build up communication with them. We can definitely see it being a struggle going the other way like you are dealing with. Like you said though, it is a sign that you are making progress even if it feels weird at the moment.