Since when I got my current phone (May 2018) I had to reformat my MicroSD card about 3-4 times, probably because of file system corruption. (It's a SanDisk 8GB one, for those who are wondering. And the previous owner had installed it on 2 devices, the first was a tablet and the second was my current phone, no problems with them. Guess I was cursed!...)
One day I turned on my phone and noticed that several apps that had been moved to the SD card were no longer functioning (toast notification saying "The app is not installed"). The other three times it just happened out of nowhere. Even today (at the time of writing), I just moved an app from the SD card back to the phone's internal storage, then the Settings app crashed. I think this also happened because of corruption.
When this happens, I cannot move/copy/edit files to the SD card and a small percentage of my files get corrupt. (Thank God this time only some useless pictures got corrupted!)
Can anyone tell me why my SD card's file system is getting corrupt out of nowhere almost constantly?