Let’s just say that topic has been put to rest. 
Xert doesn’t track it because it doesn’t fit within their model and that makes sense once you understand why. Stop lights are technically RIBs (rests in between).
Here’s one post but there are others (search for “moving time”) –
Xert Only Counts Elapsed Time - Support - Xert Community Forum (xertonline.com)
If you absolutely must have it and sync to Strava, wherever you go there you are. 
(Strava uses GPS to calculate moving time under the activity’s details.)