This fix isn't 100% tested, but like 80%.
@arkon if you're reading this, this issue is happening up stream too. I can make a issue for it in the repo but haven't checked if it happens there:
Steps:
Get Cubari source, search "cubari:imgur/3iOqiIy" change to continuous vertical, crop borders. Then back out and open the chapter again. onPageSelected isn't called because recycler position is -1. Regardless of the 4 pages you should be on
also fyi just a slight scroll fixes this issue but still
(cherry picked from commit 88fd6e5c9897d4a528f93dd02cfa2a4c644a799d)
5f0493f1e5