I’d suggest that you get a new quality SD card soon, as this type of problem could be an early indication that your SD card is failing.
thanks for the suggestion, but it is much more likely that the cause of those errors are due to power outages.
unfortunately, I have a lot of them in my area and I can’t afford to buy a UPS for every electrical instrument in my apartment 
Well that 26 GBP might stil be a good investment to make your live easier