Normalised power doesn’t match between platforms

My normalised power and average drops once the ride or race is uploaded from Garmin connect to training peaks. Any ideas guys? I have zeros included on my 810. I know this isn’t specifically Trainer Road stuff but everyone here is very knowledgeable! Thanks I’m advance

Do you have smart-recording or auto-pause turned on? If either of those are enabled, you have found the source of your discrepancy.