To control the MTU used with a subnet, maybe because you have an ipsec tunnel in the path, you can set MTU on the ip route itself:

10.95.208.0/26 via 172.31.16.1 dev br0 advmss 1300

From the doc:

advmss NUMBER (Linux 2.3.15+ only) the MSS (‘Maximal Segment Size’) to advertise to these destinations when establishing TCP connections. If it is not given, Linux uses a default value calculated from the first hop device MTU. (If the path to these destination is asymmetric, this guess may be wrong.)

https://www.systutorials.com/docs/linux/man/8-ip-route/