reset bgp all and reset bgp ipv4 all do not reset BGP sessions. Each prints an error about a missing script and the command returns status 0:

vyos@vyos:~$ reset bgp all
-vbash: /usr/libexec/vyos/op_mode/reset_bgp.py: No such file or directory
vyos@vyos:~$ reset bgp ipv4 all
-vbash: /usr/libexec/vyos/op_mode/reset_bgp.py: No such file or directory

In op-mode-definitions/reset-bgp.xml.in the two nodes reset bgp all and reset bgp ipv4 all run ${vyos_op_scripts_dir}/reset_bgp.py --command="$*". There is no such script; the reset function is bgp.py reset. On rolling, T7516 (rVYOSONEXad6b626e1b5f) uses bgp.py reset on every node. The circinus cherry-pick (fc7b3920d) changed all other nodes and left these two lines; the later backport 7ed24e2fc only touches reset-ip-bgp.xml.in.