dotnet format (latest 8) intermittently fails with "Unable to locate dotnet CLI. Ensure that it is on the PATH."

Initially opened over at https://github.com/dotnet/format/issues/2218 (forgot that it was moved...)

This started happening to our Github builds this weekend:


We never had any issues whatsoever, so initially we were looking at the newly installed net90, but then found https://github.com/microsoft/azure-pipelines-tasks/issues/19162 (and by extension https://github.com/dotnet/format/pull/2000). However, when locking to the latest version in https://github.com/icsharpcode/ILSpy/pull/3338/files we still see "Unable to locate dotnet CLI. Ensure that it is on the PATH.".

So it wasn't the old-ish version of dotnet-format that tripped us up but it happens also with the latest 8-series one. Any ideas/pointers where to start looking next? This flakiness is annoying (but not a showstopper atm).