Yes...late insomnia waves seem to be common!

I had a 29 day insomnia only setback at 18 months off. I had a few zero nights and a lot of 1-3 hour nights and that was after sleeping OK (5-7 hours per night) for about 8 months or so!
I also had a 6 week insomnia only setback at 52 months off that produced 3 zero nights and a bunch of 1-3 hour nights and that was after sleeping pretty well for over 2 years!
They both eventually evened out and good, consistent, sleep returned!
I also heard of these later (post jump or after finishing a taper) "waves" hitting others as well!
It will even out over time. I still had off nights or even 1-4 nights in a row of poor sleep at 11 months off.
I get so tired some nights I cannot stay awake, which is something I really enjoy now. In the past, prior to the onset of my sleep issues about 6 years ago, it would have ticked me off!
According to your signature, you're still on a tiny dose of an AD? And ADs in the past have caused insomnia for you. So, if that's still the case, that may be the issue? If you're completely off, then it doesn't matter. Just accept the fact that late insomnia setbacks can and do occur...but...hang in there, they won't last forever!