Progress report recording thousands of miles from strength training

Where are you seeing this? Can you provide a screenshot?

There really shouldn't be any distance recorded, as the GPS should disabled for a strength training activity.

I would try to dig into each of the 20 activities and see which ones have distance recorded. Or are all of them like that?

The activities themselves don’t show any distance that I can find. Been using this feature for years and this is the first time it has ever done this. 

I would say at least one of them has some erroneous data. You should be able to narrow it down by changing "This Year" to "Custom Dates," to see which day(s) caused the issue.

Which watch do you have? Are you running a beta version? Some users running Beta 16.13 reporting some similar issues - Strength Activities Reporting Distance

Same problem -- 13,409 miles this week seems a bit high, especially since I'm only four days in. The vast majority stems from two strength workouts. This renders related metrics completely useless. I would appreciate a fix to this please. Recorded with a 955, running 18.15.

Specifically, the Tuesday workout is to blame. I did BB squats and alternating DB lunges. 5 sets of each. Not 13K miles of lunges.

Probably best to contact Garmin Support, as the erroneous data appears to be originating from the watch or connected sensors. I see you already posted on the Forerunner 955 forum. Maybe Garmin-Sara will step in there.