Editing Pull Request Description Reverts Recent Edits

Sometimes when editing the description on a PR I find that an old version of the description populates the edit box. The result is that once I’ve made my change I have accidentally reverted some number of previous edits. Especially in a large description where I may not see everything this can go seemingly undetected and is exceptionally frustrating to deal with because I cannot trust that saving actually does what I want it to. This happens even on a fresh page load.

e.g. on this PR there are multiple instances where things get accidentally changed. Persist window layout on window close by Rosefield · Pull Request #10972 · microsoft/terminal · GitHub

Firefox Developer Edition 92.0b1
Addons used:
Ublock origin
Umatrix (with script/xhr/other allowed for *.github.com and githubassets.com)