Today the medium-lsm-multi Jenkins job failed twice. The failure was during connection close. Unfortunately there was a bug in wtperf.c and I don't know the return code. It does not fail most of the time. The time I saw a failure, it was on the 4th iteration of the script. After fixing the bug, it didn't fail (5 iterations). The only change shown in the changelog when this started are the make clean changes, which should not matter here.
This is not a crash or seg fault, but close returning an error value. For now, I'll keep rerunning that job.