Setting the HTTPS service to the default VRF explicitly fails the commit, although nothing listens on the port:

set service https vrf default
commit
TCP port "443" in vrf "default" is already used by another service!

default is accepted as a VRF value elsewhere, and leaving out vrf works. The port check treats default as a VRF device, which does not exist, and reports the resulting bind error as a port conflict.

Affected: current rolling (reproduced); 1.5.1 and 1.4.5 contain the same check (backport of T8454), not tested there.

Expected: vrf default behaves the same as no vrf option, and the port check reports "in use" only when the port really is in use.