The application should be on the newest standard after starting the process of updating via the Mac app store. After the update the blue button on the App's page should turn from "update" into "open".
The download bar shows the progress, then indicates that it was downloaded (bar is full and Launch-icon in bar "jumps"), but in the App Store the "update" button is visible again. Clicking it again repeats this process.
No special script
There is nothing I can do. It all depends on Apple's cloud.
Some useful hints though:
https://apple.stackexchange.com/questions/345857/mac-app-store-downloads-just-dont-start-mojave
You could goto $TMPDIR/../C/com.apple.appstore and find the right one. One good way is to remove everything in $TMPDIR/../C/com.apple.appstore and then click Update button. The only folder in $TMPDIR/../C/com.apple.appstore like 2D15B9C4-..... is the one contains .pkg file for Tampermonkey. Then you could install it manually.
Reinstalling it seemed to fix it (for now)
Updating Tampermonkey while Safari is closed fixed this for me.
It is too expensive to install TamperMonkey from App Store.
I will turn to chrome to use Tampermonkey.
Updating Tampermonkey while Safari is closed fixed this for me.
thank you Ekonoms, why didn't I think of that
Updating Tampermonkey while Safari is closed fixed this for me.
@Ekonoms Yes, this fixes the issue. Thanks for pointing this out.
Most helpful comment
Updating Tampermonkey while Safari is closed fixed this for me.