Hi again forum. Just stumbled upon a thread on reddit of a IMSB failure of a replacement dual row LN bearing , where the IMSB is obviously completely damaged, but the rest of the engine survived as it was done just in time. Failure was 21k miles after installation.
As described there was metal in oil upon purchase, and buyer knew there was a problem, therefore the tear down. Seems he has found no other explanation to why the bearing has failed. LN has received the bearing so they will probably do a post mortem on it.
After reading here for a long time i have been given the impression that these dual row bearings "never fail", and have no recorded failures. Just wanted to post this to record that these to, can fail (all thou very rare it seems).
https://www.reddit.com/r/Porsche/s/ktJdcZzYXy