On my Fenix 5x I made the silly mistake of saving a location and renaming it 'Car' more than once at different locations and different times, without deleting previous 'Cars'. I figured that the firmware wouldn't let me do that if it couldn't handle it, but it did, then I guessed it would sort itself out and display them by distance away from me and sure enough, at the time, it did seem to work that way. I thought that was rather clever, at first...
Then one day I tried to 'navigate' to the location I had saved for 'Car' a few hours ago and found that all the 'Car' locations were the same 10.5 km distance and I knew I hadn't walked that far this time! It turned out that the location I had recently saved had gotten replaced somehow by a previous one. All the 'Car' locations (2 of them) seemed to be the same!
Thinking that this device (or I) was crazy, (and after finding my car) I drove home and saved locations at a number of traffic lights and gave them all the name 'A'. At first it seemed to work and the first two stayed distinct, so I was concluding that I had done something wrong, but on the third one the last two saved locations took on the same distance and position. It does seem there is something crazy going on.
Anyway, the takehome message is 'Don't use non-unique names for saved locations' Instead of backspacing over the date, append 'car' or whatever to it (there is no easy way to pre-pend things). It's a bit messy, but better than losing your car....
Terry