At least for the external card in the phone, the folder was never properly indexed.
Often going under 100GB when it's almost full and is a 256GB card. That top folder should then say about 240GB or above, not 100GB or under.
It seemed that it could only scan files directly under the folder you have selected to monitor regardless of sub-folder option being enabled or not.
One test I did was to just search every folder with a command I don't remember in Explorer, I can edit this with it later when I am home..Anyway, it allowed me to see all folders..So I selected them all to be monitored.
I don't know if this actually made it possible to see the files. I was only looking at folders because if the top folder is 256GB or around there in size, as it's often full, then I know it works proper.
But I don't want to rely on monitoring the thousands of folders..I think it also goes folder to folder in scan, so as there are a bunch of semi-duplicate monitors the scan takes a lot longer than it would if only the top folder was indexed and the sub-folder indexing worked.
It also can't monitor changes, I don't believe. I could always make fresh tests, if need be. But less tests are better, I think, for the longevity of the cards.
I can't speak of the internal card, I didn't pay the same attention to it. But I can always find out when I get home and answer any questions, if I can find out the answer.
As some other threads seem to indicate scanning Android devices works fine, it can either be that I have the wrong option set for monitoring the phone when plugged in, I think it's 4 options where one is file transfer and another is just charging, or/and my phone is slightly broken in either software or hardware. Wi-Fi enabling lags the phone hard for several minutes or until turned off, started some time at or after getting superuser. Maybe it's relevant, I don't know. Maybe I installed a system image that is a bit broken for working with EBV, I never thought to use EBV for the phone before 2024 I don't think, so I have no experience with how it behaved pre-rooting and that slightly different system image.