Choosing the “Use laps” option always seems to start and end the intervals too soon. I’ve attached a screengrab from a ride in which the lap button was pressed at the bottom and top of a climb. You can clearly see where the effort began and ended from the elevation and from the W’ graph. As you can see, the interval starts and ends in the wrong places. This happens every time I use laps. Any ideas what’s going on?
I had exactly the same issue. Apparently this is linked to a Strava API bug when you have the “privacy circle” enabled. So you need to disabled then, and your laps will be at the right place 
Hmm, yes, I do have privacy zones enabled - but doesn’t everybody? I’m not going to turn these off, as they’re a pretty essential protection. That’s disappointing.
Yes if you have the privacy circle turn on the Strava API does make a mess of some of the laps. There are other issues with lap data from devices not matching the .fit file traces but that only applies if you are using Garmin sync or uploading .fit files.