Garmin Clipboard pace difference with Garmin Connect

Hello everyone!

We are facing some pace differences with planned workout on Garmin Clipboard and Garmin Connect when workout it's synchronized. It happens in many kind of devices, like high, mid and low end. 

What could be causing this? maybe Connect adjust pace based on health and performance metrics of each athlete? maybe workouts are calculated with performance metrics and when syncs to Connect app are calculated again?

Forerunner 965

Garmin Clipboard iOS app

Thanks in advance!