Thanks, that makes sense.
In that case I will revert the source tags on the ways back to their original values and only keep the actual change (converting the units from km/h to mph where needed). So those edits will not add a new source tag on the objects themselves.
The dashcam source is mentioned because our usual workflow is to verify lane counts and turn:lanes information using dashcam footage.
While working on this area I also found quite a lot of other issues that can be detected automatically, for example typos in tags like turn:lanes=riiight and similar mistakes. At the moment I’m checking and fixing these manually one by one.
Do you happen to have any suggestions for handling or validating these kinds of errors more efficiently?

Hi, thanks for checking this.
My understanding was that a source tag should be provided when making edits, so I chose source=gps because it seemed like the closest option at the time. However, I realize now that this may not have been the most accurate choice.
The reason for these edits is that we ran a query across the whole area after noticing during our tests that in several places our OSM-based navigation was producing incorrect speed values. This happened because the speed limits in the area should have been interpreted as mph, but the missing information caused incorrect conversions.
Because of that, I started fixing these segments in OSM so the data would be clearer and would not cause similar issues in the future. Unfortunately I haven’t finished correcting all of them yet.
For future edits, would you recommend not adding a source tag in cases like this, or using a different one?