For me the offer to replace the battery compartment came just in time.
After a year of flawless use, I (again) had to change the batteries, what I did.
With the new batteries inserted, the pedals were working for about ten minutes until I got the first drop-outs. This got worse and after about an hour, the connection was completely lost.
The new batteries are 5.4mm thick while the empty removed ones were 5.45mm thick.
Bought new batteries of a different brand with pretty much the same result.
The day after I tried the second set of new batteries, I got the offer from Garmin.
Yesterday I finally got the replacement parts and right now I will install them.
My Vector 3s already had the revised battery compartment design when I bought them.
The design of the replacement parts seems to have contact springs with more range of motion, so hopefully they aren’t as susceptible to expanding batteries as the previous ones.