webpack-cli: Uncaught exception: TypeError: callbacks is not iterable

Describe the bug

I’ve just upgraded from v4 to v5 and have stumbled upon this error:

[webpack-cli] Uncaught exception: TypeError: callbacks is not iterable 
[webpack-cli] TypeError: callbacks is not iterable 
    at done (C:\Users\me\repo\oas-web\node_modules\webpack\lib\cache\ResolverCachePlugin.js:218:34)
    at C:\Users\me\repo\oas-web\node_modules\webpack\lib\cache\ResolverCachePlugin.js:160:28
    at jobError (C:\Users\me\repo\oas-web\node_modules\webpack\lib\FileSystemInfo.js:1559:5)
    at C:\Users\me\repo\oas-web\node_modules\webpack\lib\FileSystemInfo.js:1795:8
    at C:\Users\me\repo\oas-web\node_modules\webpack\lib\util\AsyncQueue.js:104:29
    at processTicksAndRejections (internal/process/task_queues.js:79:11)

According to the source code it assumes that it can only be and array or undefined even though false is set in the code itself. It might be a another bug causing the false, but it should be handled, right?

What is the current behavior?

It fails every time I start my DevServer.

To Reproduce

Steps to reproduce the behavior:

We have a pretty complex setup with a monorepo. It’s going to be hard to share. But if it’s needed to fix the code I guess I can put in the time.

Expected behavior

Build should not fail when I start my DevServer

Please paste the results of webpack-cli info here, and mention other relevant information System: OS: Windows 10 10.0.17763 CPU: (12) x64 Intel® Core™ i7-8850H CPU @ 2.60GHz Memory: 4.54 GB / 15.81 GB Binaries: Node: 12.16.1 - C:\Program Files\nodejs\node.EXE Yarn: 1.16.0 - C:\Program Files (x86)\Yarn\bin\yarn.CMD npm: 6.13.4 - C:\Program Files\nodejs\npm.CMD Browsers: Chrome: 86.0.4240.111 Edge: Spartan (44.17763.831.0) Internet Explorer: 11.0.17763.771