One quirk with the CARV units. They look identical, but when you pair to they phone/app the first time, they get assigned Left/Right depending on which foot insert they were attached to (since the foot inserts have left/right, of course).
If you disconnect the 2 modules that attach outside the boot from the cables coming from the foot inserts, you have to keep track which was connected to left and which to right. Otherwise, the app will complain that they were incorrectly attached our not even pair properly.
I put the R from the CARV sticker on one of them to identify as Right-
View attachment 116918
And of course, I put the sticker on the left one instead.