(In reply to :Gijs (he/him) from comment #5)
(In reply to Jared Wein [:jaws] (please needinfo? me) from comment #4)
Thanks, I was able to reproduce it now. I'm ashamed I didn't know how to find it before.
Since this bug is not reproducible on desktop, the issue likely isn't related to the Readability library or ReaderMode.jsm but some customizations made by Firefox Preview. Firefox Preview bugs are tracked on github at https://github.com/mozilla-mobile/fenix/issues. Can you please file the issue there? Sorry I can't be of more help.
TBF, it might still be a reader mode bug if Fx Preview gets sent different input than desktop for this site, which also seems plausible...
... except if I request the desktop equivalent it also doesn't work in Firefox Preview (while it works on desktop).
I don't know how to connect to Firefox Preview and do debugging on the device, or how this feature works in Preview - it might not even use readability... Nick, who knows more about whether it makes sense to keep tracking this as a reader mode issue?