Have just updated to GPS 2.90.
updated to 2.90 this morning before a run and it got GPS fix within a few seconds. Also did a MTB ride this afternoon and again GPS fix was almost instant. Previous 2.8 and 2.7 took ages to get a fix and ended up doing some activities without GPS. 2.90 Seems to fix this.
Did you figure this out? My OWS are a mess and my GPS version on 945 says 4.10. Called Garmin they said it should be 2.9 had no idea why mine said 4.10. They had me update all my maps in Garmin Express and 3 hours later GPS is still the wrong version, 4.10. Frustrated. My runs are fine. It's just OWS. Thanks
If you have updated to the latest public release - https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-945/220507/forerunner-945-updates-sw-4-40-is-now-live
then your GPS version should/will be 4.10.
I swam with a 945 this morning without any problems

As did my other half

Hi, have you figured this out yet? I am having the same trouble.