Tag quality of invalid path no longer "Not Found", now "REFERENCE_NOT_FOUND" after Tag Provider resave


Only a few moments ago, retrieving the quality of a tag which doesn’t exist, within an indirect binding would return “Not Found” as the result. However upon resaving the Tag provider, it is now returning “REFERENCE_NOT_FOUND” instead?

I have a bunch of expressions using:

toStr(tag("TagPathThatDoesn'tExist")) = 'Not Found'

as well, and again, this is now false as the toStr(…) part returns the REFERENCE_NOT_FOUND text now.
I’m quite confused, as it was literally working 5 minutes ago before rebooting the tag provider…

PS. I realise that I should be using isGood(...), but this is legacy stuff that I’ve had working for ages.