It works for me, so we need exact reproducing steps.

dmbaturin@vyos# set interfaces bridge br0
[edit]
dmbaturin@vyos# set interfaces ethernet eth4 bridge-group bridge br0
[edit]
dmbaturin@vyos# commit
[ interfaces ethernet eth4 bridge-group ]
Adding interface eth4 to bridge br0

dmbaturin@vyos# run show bridge 
bridge name     bridge id               STP enabled     interfaces
br0             8000.0050569b18ed       no              eth4

Oh, sorry, I misunderstood the issue. It's the "run show bridge brN" command that is not working, while the "run show bridge" command does.

https://github.com/vyos/vyos-1x/commit/db53284fb416d8d625b7a66c0b92df35b92a1f0e

My attempt to use github's editing GUI didn't go well, sorry for the poor commit description.

@runar Please note that variables inside single quotes do not expand in the command templates, just like in shell, so it was literal '$3' string that was passed to brctl instead of the value of the third command word.

Ahh, my mistake! Will remember that :)