MM transformed to mm in product explorer

this is not a big problem but it is definitely weird so I thought I would report it.

I have a child category called MM. it appears as MM in mysql and appears as MM in front end (as far as I can tell so far anyway) but is transformed to mm in backend category/product explorer. I even renamed it, let it be for a few days, and then renamed it XX (which shows in capital XX letters in prod/cat explorer) then back to MM after a few logouts and computer reboots and there it is as mm still. weird.

it's not a problem for me necessarily since it seems to be appearing properly in front end but I find it very odd, cannot figure out why it is happening and want you to know about it in case it might signify some other issue.

Category names can be translated via the translation files. That's mainly used for order statuses which are handled as categories and which are translated by default thanks to the translation file. In the translation file of HikaShop, you have MM="mm" for the credit card month field. So that's why you get it as lower case in the back end interface.