I added *.vpwhistu to "Default Excludes" in Tools->Options->Editing->Search, made <Default Excludes> equal to:
<Binary Files>;*.vpwhist*
Now when I do "Find in Files" the searched text (which is present in the .vpwhistu file) is no longer shown in the search results (it was in the search results when *.vpwhist* was not in <Default Excludes>).
However when I then go to "Replace in Files", and keep using my <Default Excludes>, it does now find the term in the .vpwhistu file and is asking to replace it, even though *.vpwhist* is in <Default Excludes> and it doesn't show in "Find in Files" results - it still asks to replace it.
I'm using 27.0.1 on Linux x64.