Missing statistics case for multiple mechs in your garage:
Happened to me today. Got in the game, checked my stats and noticed how many of my duplicated mechs and also some of my main mechs had no statistics nor their correct rank (everything was zero; thus rank and stats) for no apparent reason.
Solution I've found and which may save some headaches well to the pilots suffering of this situation and to the support guys as well:
If this happens to you then just explore a map for a while with a mech with missing stats and quit the match. Check again your pilot profile -> mech profiles and voilą. All statistics and ranks should be there again as they were before ahving the issue.
Hope this helps! ;)
--> To the guys running help and assistance topics in the forums: Feel free to add this solution to your lists, please. Thanks.