Heartbeat even firing too frequently

UE newbie here.

I just built UE 4.21 for linux, by getting the zip from github release branch.
I fired up the engine, chose a template, and pressed “Launch.”

Now the editor seems kinda frozen, and I see a lot of these messages in the log:

LogUnrealEdMisc: Warning: Heartbeat event firing too frequently (21.562 sec). This should never happen. Something is wrong with the timer delegate!

Should I be worried about this warning?

Also, is a “Launch” supposed to take a very long time?