CTRL-V not pasting into certain web apps in Abrowser

Kia ora everyone, As of a few days ago, I'm having a bit of trouble using CTRL-V to paste things into certain web apps in Abrowser. I'm using vanilla Aramo with all the latest updates. I do have NoScript and uBlock Origin installed, also with the latest updates. The apps I'm having trouble with are RoundCube webmail and Element chat.

RoundCube: I can paste with the right-click menu, but not CTRL-V. Which is a minor nuisance for me, but a major accessibility issue for people who rely on these sorts of keyboard shortcuts to make their computing manageable. Curiously this is only a problem on the instance hosted by Disroot.org, it seems to work fine on the RiseUp.net instance. The Disroot crew have just put RC in place as a replacement for their old RainLoop webmail client, so it could be they are running a newer version, or that they've customized it in some way that has broken CTRL-V pasting.

Element: Pasting does not seem to work at all. I've tried both the chat.iridescent.nz instance hosted by the homeserver I use, and the official trial version at app.element.io. I've always had the same issue with Discord (when I'm forced to use it), so I suspect it might be something to do with an underlying UI framework that Discord has always used, and that Element Web has recently shifted to.

I haven't yet raised the issue with the Disroot team or the Element Web team. I thought the best first step was to see if others using Trisquel have struck the same problem, and see if we can narrow down the possible causes, before escalating it further.