PPTP tunnel bet two RB1100AH droping packets

I have a two PPTP tunnels between two MK: RB1100AH2 and RB1100AH.
When I ping from AH to AH2 using PPTP tunnel I drop 1% to 2% of the packets.
When I ping from AH to AH2 using WAN I don’t drop any packets.

Two tunnels setup over two different ISP in case one goes down. One tunnel is handing traffic at a time.

Any suggestions welcome.


Dave