I can confirm: using the new 220.127.116.1120 patch I see no more “Download failed” thing, no more blank menus, no more slow UI. I’m using Linux (SC running under wine-staging, Win7 compatibility settings).
On Win7 native host and 18.104.22.16802 patch, I wasn’t able to reproduce any of the aforementioned issues.
I don’t want to speculate, but it looks to me that something terrible going on inside UI threads. My thoughts that wine introduces significant delays when processing various events and a UI subsystem don’t expect that. Lack of proper synchronization and race conditions? Probably that’s what happening on some Win machines as well?
Nevertheless, given the profile of bugs you’ve discovered I strongly against bringing back the new CEF (I suppose this is a component you’ve updated?) into the SC just for “compatibility reasons”. I encourage devs looking into this thread to fix bugs or at least provide decent workarounds.
Otherwise, it is a matter of time when this will hit my Win7/Win8/Win10 machines as well.