KNX received service acknowledgment with wrong send sequence

Hello.
Suddenly my KNX interface is starting to send me warnings in the log saying:

  ] - [KNXnet/IP receiver] KNXnet/IP Tunneling 192.168.50.10:3671: received service acknowledgment with wrong send sequence 107, expected 108 - ignored
[WARN ] [tuwien.auto.calimero                ] - [KNXnet/IP receiver] KNXnet/IP Tunneling 192.168.50.10:3671: received service acknowledgment with wrong send sequence 96, expected 97 - ignored
[WARN ] [tuwien.auto.calimero                ] - [KNXnet/IP receiver] KNXnet/IP Tunneling 192.168.50.10:3671: received service acknowledgment with wrong send sequence 192, expected 193 - ignored

What does this mean - and how to solve it?

Running OH2 KNX Plugin 1.9, connection in Tunnel. ABB IPR/S 2.1 IP Router