Sudden HUGE increase in FTP when cycling while wearing Vivoactive 5 and using my Edge 1030 as usual

Last week I replaced my old Fitbit with a Vivoactive 5 watch. The next day I went for a ride as usual with my Edge 1030, wearing the Vivoactive. The reading from the power meter was OFF THE CHARTS (~2500 watts…crazy!) I was able to change the data for the ride but it did exactly the same thing on the next ride, and I’d like to fix it so I have normal power and calorie readings again. I tried recalibrating my power meter but I get an error and it won’t complete the process. Anyone experienced this before? What’s going on?