It shouldn’t make any difference with Avast Premier turned off (unless you also disabled AOS) as that would have no bearing on the AOS browser extension as once installed it is effectively independent of Avast Premier.
It isn’t so much being able to install AOS without avast (in regard of the bug) but AOS being essentially independent of avast when avast is disabled, AOS is still running in the browser.
Any bug in AOS could still be present, if it is indeed an AOS bug. I’m not entirely convinced of this or I would have expected to see more reports in the forums, I would also expect it to be seen happening in other web sites and not just here in the forums.
Personally I never chase an error the first time it occurs, even the second or third time if it isn’t a regular occurrence.