..just off converting some fit files to xls to work out why the fenix 5 plus's activity for runing with HRM-RUN die at 2:09mins into an activity for advanced runing dynamics, and the recurring activity error is a Data 6 event logged that then kills the recording of that data subset.
If anyone knows much appreciated thanks as my debug of the android phone with garmin connect shows no timestamp errors, so i am looking at this Data 6 event as the problem originating from the watch itself.