Not seen this happen before. Just over 3,000kms in, 11 speed chain that came with the SLX groupset. Just one single roller out of the whole chain. Popped out the offending inner link, installed a new one with joiner pins, all good. And incidentally, 10 speed joiner pins seem to work just fine on 11 speed chains. Was short of an 11 speed pin, busted out the micrometer & verniers, measured up a 10 speed pin, couldn't measure any difference, so in it went. Done 22 kms on it with 630 meters of elevation, all good.