I'm using PlayFabClientAPI.LoginWithCustomID and setting InfoRequestParameters.GetPlayerStatistics = true (along with some other fields GetUserData, GetTitleData and GetUserReadOnlyData) - and most of the time this works fine and I get the player statistics back in the GetPlayerCombinedInfoResultPayload.PlayerStatistics field.
However, occasionally the login result has all the other fields correctly filled in (UserData etc) but the PlayerStatistics payload field is empty (PlayerStatistics.Count == 0). If I run my game 10 times in a row, logging in with exactly the same account / request parameters each time, about once or twice I get no statistics (but get the user data 100% of the time).
It seems very odd that this is non-deterministic. Is this a known bug with login? Should I be getting player statistics after login, rather than at the same time? Or is there something else going on here?