I thought that the original recall reason was to do with an air con drain venting into the UJ and causing rust and premature failure. Given yours had gone at the rear, unless there’s a drain in that position then that reason doesn’t sound right. Corrosion or grease loss are both listed as ‘replace’ reasons.
I noted on newtis that although it is possible to drive the car with a faulty, doing so requires the transfer box to need recalibration.
This instruction looks like the recall notice actions (copied from the E71 but has the same issue and my prop shaft was replaced ...
https://www.newtis.info/tisv2/a/en/e71- ... 1VnYfMxH37