Pipeline cache seems not to be working

[SommerEngineering]

We have been observing for a few days that our build pipeline is no longer using the caches. The cache action claims that no suitable cache was found -- although this is not true: as we can see in the list of caches, the keys already exist. This issue is known for some time but has not yet been resolved:

• cache restore on versions 3 and 4 not working actions/cache#1361
• Cache action fails to match successfully uploaded key actions/cache#1198
• Cache miss on Windows despite a successful cache-write actions/cache#1275
• Unexpected cache misses since Feb 17th actions/cache#1114