Preferred wearable change lead to significant data change

I have a Edge 1040 computer and a epix watch. It's currently winter so I've been doing a lot more training on the indoor trainer as such I changed my primary wearable to my watch. All numbers were consistent with training as the epix as primary wearable, including VO2 endurance etc. I went for a ride recently and used the 1040, after uploading this ride all the numbers when Haywire including a 5-point drop in VO2 comma a significant drop in load, endurance and recovery. I've deleted that activity and I've changed the primary device back to the 1040, none of which have worked. Does anyone have any suggestions as to why this would occur and a way to rectify?