Packet Losses to some Hosts

Hi,

I have three Windows hosts in a ZT network. Let’s call them A, B and C. All running ZT 1.14
A is able to ping C without any drops. Latency stays below 60ms.
B is able to ping C without any drops. Latency stays below 60ms.
Ping A to B: Packet loss every few seconds. Sometimes the latency grows to 200ms for a while.
Same for B to A.

Any suggestions?