In case it's of use, I had this issue with a ServiceBusTrigger function. I updated the core tools but it did nothing to solve the issue. I could not find the referenced version of WebJobs anywhere. I had to downgrade Microsoft.Azure.WebJobs.Extensions.ServiceBus to 5.8.1 to get it ...
It picks up not only the Function types, but also your "other” public types. During the checks (if the necessary attributes are present) it loads dependent assemblies (indirectly - to get the parameters of the methods). During this step an error occurs. The workaround (see my comment on...
Could not load file or assembly 'Microsoft.Extensions.Logging.Abstractions, Version=3.1.19.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified. at System.Signature.GetSignature(Void* pCorSig, Int32 cCorSig, RuntimeFieldHandleInternal fieldHandle...