IRequestPreProcessor not executed

[MilivojeMishikj]

I have two preprocessors for one request.
One is declared as
public class PreProcessorA : IRequestPreProcessor<MyCommand>
the other as:
public class PreProcessorB<TRequest> : IRequestPreProcessor<TRequest> where TRequest : IMyInterface

Before the IRequestHandler.Handle is processed then only the PreProcessorA is executed, but not the PreProcessorB.
Another symptom is that the PreProcessorA is executed twice.

I register the with
.AddMediatR(typeof(MyCommand)).

My version of MediatR and MediatR.Extensions.Microsoft.DependencyInjection is the latest, v.10.0.1.

I found a similar issue (jbogard/MediatR.Extensions.Microsoft.DependencyInjection#58) but it seems it was resolved some years ago (jbogard/MediatR.Extensions.Microsoft.DependencyInjection#59).

Thanks in advance.

[MilivojeMishikj]

Declaring PreProcessorA as below resolves the issue:

public class PreProcessorA<TRequest>
    : IRequestPreProcessor<TRequest>
        where TRequest : MyCommand