Player changes ID over lan.

In the latest snapshots (since ID was introduced to allow name change) my friends id (eg. 38974-2uhdai-w97.dat) is changing time to time, he has the same account and havent change name either, we play over VPN LAN and the only way to solve the problem is to rename his old playerfile name with his new ID cause otherwise he will start a new character,as said this problem was not possible before the name-changing-update.