There seems to be a UI bug with the quote button on mobile. I’m experiencing that quoting is aborted as soon as I touch the quote button with the highlight handles.
I’m using Fennec F-Droid on a FP1 with Kitkat 4.4.2
I can confirm this for the left border of the “Quote” box with Fennec F-Droid 65.0.1 on LineageOS for microG.
Highlighting doesn’t stop when touching the other borders for me.