That wouldn't affect video playback. I wonder what it shows once you try playing the video and what shows up on the network tab. I'm on macOS 10.15 as well with Chrome 80 and haven't experienced this. I wonder if there is some other kind of networking issue at play here.
Great question. In situations where Action Text is used in a CMS or Blog, it can be a bit difficult as you probably wouldn't run the text through a translator. You could have multiple Action Text attributes on a model for each language or build a mechanism around Action Text which takes it into consideration, but I don't think that it natively supports i18n. https://github.com/rails/actiontext/issues/32 is about the only thing I could find in regards to it.
You could add this to your Gemfile to see if it helps. Alternatively, you could upgrade Ruby version to 2.6.5. There shouldn't be much breaking changes between 2.6.3 and 2.6.5.
