No fastest 5k running award

The last few weeks I did multiple 5k runs and even a 10k run, but did not get the award for the fastest time.

i got all the other awards like: personal best (calories and distance), 5k running and 10k running.

is it bugged or is there anything I did not understand how to get it?

ios 16.1 watchOS 9.1

Thank you for any advice.