Cannot export 2nd archive using Xcode 12.3 on Big Sur

I have Xcode 12.3 running on both Catalina and Big Sur. I have a strange problem that only exists on Big Sur.

I can build an app, archive it, and export it with no problem. But if I try this again, it will fail with the following error message:

Didn't find executable for bundle NSBundle <(null)> (not yet loaded) at path <DVTFilePath:0x7fc9f1948fa0:'/Users/$HOME/Library/Developer/Xcode/Archives/2020-12-21/MyApp 2020-12-21, 9.26 PM.xcarchive/Products/Applications/MyApp.app/Contents/Library/QuickLook/MyAppQL.qlgenerator'>.

I can export previous builds, but not the one I just made. Nor can I export any newer builds. Once I get this error, no more exporting.

To fix it, just quit Xcode. Now I can export the previous build with no problem. I can also build one more app and export that one, but only one. After that, I have to quit Xcode again.

It works fine on Catalina.
Apparently, this is a known bug: https://developer.apple.com/forums/thread/668919
Cannot export 2nd archive using Xcode 12.3 on Big Sur
 
 
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