ping loss with ipsec tunnel on RB750Gr3

hello all,

usually i configure an ipsec tunnel between RB750GL and RB1100AHx2 and it works just great.
recently i changed to RB750GR3 (instead of the GL) and used the same configuration. but I have almost 30-40% of pocket loss..
what should I do different?
the pppoe interface works just fine without disconnections…