Server response is encapsulated with IPv6

[sanaa50]

I have two client-server model, one for TCP and the other is for UDP. I tested these two models with mininet using sudo mn , and they worked just fine. After that, I tried to run the models in a simple mininet network of two hosts and one P4 switch. The packets of the client request are being received by the server, but (by reading the switch log) the response of the server is encapsulated with IPv6, which can't be possible since the client uses IPv4. Consequently, no reply from the servers.
I double checked my P4 code and switch runtime json file. I can't see any problem.

I really need help.

Note: Sorry for my poor English.

[njlnc]

Have you solved the problem yet? I had the same problem.