Phone heats up, hangs and restarts due to problems with the media index.

Question

A few times a week my phone heats up, hangs, and goes into a restart loop every few minutes, which drains the battery quickly. After some research in the diagnostics app I have come to the conclusion that it is the Media Storage app that hangs. I see spontaneous restarts in the android.process.media process every few seconds. A work-around is to go into settings, apps, all apps, media storage (Lagring av Media, in swedish, or android.process.media in android) and clear data. This immediately stops the problem, but then I usually need to reboot the phone manually once to get it to rescan all media again, since all that indexed data was lost.
I suspect that my sd card (SanDisk microSDXC Mobile Ultra 128GB (Class 10)), with 90GB of MP3 files has somehow related to do, or at least makes matters worse, although I haven't tried to go for a week without it. The media data is usually around 50MB, when I clear it, this quickly rebuilds, until next time...
The media storage index seems to be prone to corruption, and/or one or more processes reading or writing is corrupt.
This is a nuisance since if I don't catch it rebooting right away I can be without battery quickly.
So, even though the fix is easy now that I've found it, I would rather not have the problem at all. Worst of all, is when this happens when I'm in a call, or when someone tries to call or text me, but I don't notice, since the phone is hung. Also there is nothing wrong with the phone, this must be a software issue, where an error isn't handled correctly.
In the early days of researching this problem, I did a factory reset, which actually cleared up some other issues I'd had with bluetooth connection in the factory installed software (even though it was of the same version). After this I waited to install any apps, and just went with standard vanilla android and sony apps. Still the same problem occurred after a couple of days. So it isn't related to third party software either. I see lots of posts online which detail this workaround, some as old as a few years old, but none with a real solution.
Help please?

Answer 1

I recieved a reply from Sony Xperia Care support. They suggested removing the SD-card to see if that helped. Fingers crossed I have now gone three days without acting up. The next time it does I'll try removing the sd card and see if I can break the record of seven days without a problem.
They claim that it can be a hardware fault with the SD-card (highly unlikely in my opinion). Or a corrupt file on the card. I have only used the phone operating system and the Sony PC Companion application to transfer files. None of them have warned me about corrupt files. Also, if I can go seven days without a problem, why not eight? It's not like it acts up every time I access a particular file. It's just random, and rarely when I'm doing anything that access files on the sd-card.
My guess is still that the media storage indexing is buggy. It's much more likely that the storage index is corrupt, than a file, for this behaviour to occur. Note that I work as a software test officer, with 25 years of IT experience, so I have a vague idea what I'm talking about.