Here [0] is a core dump analysis on a debug image (alebeit for an older commit).

> tap_features = 28979

If I understand correctly, Linux reports the device is multi queue capable.
My current hypothesis is that in that case args->num_rx_queues applies (not overriden to 1), but .api file has not included that field in [1], and neither does .api.c sets 1 as a default, so zero (from memset) applies.

[0] https://logs.fd.io/production/vex-yul-rot-jenkins-1/vpp-csit-verify-device-master-1n-skx/4856/archives/log.html.gz#s1-s1-s1-s1-s1-t1-k3-k4-k1
[1] https://gerrit.fd.io/r/c/vpp/+/23434