Untraceable long operation (query?) during backup

I’m not sure it would log. I have it set, but the code is missing the parameter I guess it should give:

EDIT: had the wrong ExecuteNonQuery reference before

In terms of the ExecuteNonQuery call, I’m not sure where it’s wanting to go, but I wonder if it’s here:

Perhaps you can figure out the calling to see if you can get that INSERT loop logged, or breakpoint it.
It sure looks like a loop to me. You could try breakpoint and/or log something after loop, near Commit.
If Visual Studio can actually pause the program, some thread might be seen in the middle of the loop.
There are lots of threads though. My debug approach (using dnSpy) would probably try to breakpoint.