I have done several runs above 25km up to 42km which are shown in my activities on Connect but my personal record in Connect remains 25km. Can I add the longer runs to my records and why would it not be showing them anyway?
If it isn't updated automatically and you have approved all records then you can set the record manually. Go to the activity in Garmin Connect Web. Click the cog wheel and click Set as PR.
I think it is greyed because it is a trail running activity. It will likely work if you switch to running. A workaround is to switch to running. Set the PR. After that change back to Trail running.