Hi,
The last two times I set a record while running it seems my 1KM and 1 mile record have disappeared.
Last Sunday I ran the marathon in 3:05 (so avg of 4:24/km). My Epix 2 suggested this was a new PB and I accepted this. Yesterday I did a recovery run and afterwards I was presented two new PBs: 1 KM in 5:18 and mile in 8 something. So much slower than my average marathon kms/miles.
I also noticed this behaviour a couple of weeks when I ran a half marathon PB. Also after that the next run I set a new (and slow) PB for KM and mile. I didn't pay too much attention to it at the time, but since I happened again now I get the feeling this is related.
This only happens to KM and mile PB which (as a coincidence?) are not logged as records in Garmin connect, but only on the watch itself.