For those who noticed that Reader was… let’s put it mildly, rather dysfunctional with recent Nextcloud releases it may be worth knowing that I made a new release which brings it back to life. Functionally there is not that much change other than that it now works reliably on public pages, the main thing is that it works again.
Look for Reader 1.5.0 or later, older releases do not work in current Nextcloud.