Sight 'n Go problem

I have a two month old Fenix 6x. Sapphire

I fly free flight model planes and use the watch GPS to navigate to them when they have landed. I use the Sight 'N Go but as its only accurate to five degrees I use binos with an internal compass to take the reading. I then go to Sight 'N Go, turn the watch until it shows the bearing I want and push start - Voila, it draws a line down the bearing and away I go

Until yesterday all was well. I used it yesterday and suddenly its out by 23 degrees ( which happens to be the angle of declination here). eg lets say my bearing in 200 degrees. I do Sight N Go and up comes the compass. I turn the watch to 200 degrees and select it and it sets a bearing of 177 degrees! 

The navigation is correctly set to magnetic

also, project waypoint works correctly, but this is too slow for my needs and the watch should work as described

I have tried
1) turning the watch off and on
2) manually setting the declination angle
3) setting the watch to true north and back again
4) updating software to 20.50
5) resetting and putting all the settings in all over again
6) changing the GPS to GPS satellites only in case it was an issue with the Russian Satellites and the current war.

None have worked

I have a friend who bought one at the same time and I suspect his was doing this from the start

Anyone else have this issue? - its probably uncommon as very few people would use the watch as we do Im wishing I hadnt sold my Fenix 5!