Frozen during open water swim

I did my second activity this morning with F5+T and the watch froze completely after 2mins 26s.
i used GPS+Galileo.
i could only get buttons to respond by holding down the top left button to reset the watch. The display said 73 metres (I had swim almost 300 before resetting) and now this is the record in Garmin connect

https://connect.garmin.com/modern/activity/2797428977

after reset I changed GPS to GPS +Glonass and the swim was perfect. Not sure if it is coincidence or not that I changed the settings and it was ok

https://connect.garmin.com/modern/activity/2797429137

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