Hello,
In order to get MTU 2000, a subinterface which is configured with 'rewrite ingress tag pop 1 symmetric' needs to be configured as 2018 MTU, and if configured with 'rewrite ingress tag translate 1-to-1 dot1q 555 symmetric' needs only 14 overhead -> 2014, in order to get 2000 MTU
I've only discovered this 2 cases for now.
Which exactly is the explication, seems related with overhead 14 (Ethernet) and 4 (Vlan), but in both cases are subinterfaces.
Thank you!