Yes, it sounds like an error. I am not aware of a paniculata reblooming so I emailed them and have not received any notices (so far) and the webpage has not changed. Take it with a grain of salt for now. It should have said "As it blooms". If they ever reply, I will try to remember to post again.

Based on the pictures in the link it looks like the stems terminate in a flower at varying times instead of blooming uniformly at one time across the whole plant.

I wouldn't call it reblooming , but I've pruned off some panis. stems midway into the season, and a new bloom remerges out of it as well. It's not reblooming in that sense, but a delayed bloom on a already flushed out shrub.

I have observed that as well.

I tried that one year here in MN and they did ok. Pruned on June 1 and bloomed in September instead of July.

This may be locale dependant. Right now, my Panic. are somewhere between mid lime - starting to become white and more fuller blooms. I was thinking to myself , just perfect timing as some of mac's have started to fade. I never used to notice these details at all until this WFH thing - slight slower pace . Another detail that I noticed that I never knew on the LL blooms for example. It's not like 1 floret dead center that makes the bloom profile. There appears to be 3 - 1 dead center, and one to the left and right, a smidge below. ---all little details - that never were on my radar