Tex:
This relates only to the neutral bars here in USA
"408.41 Grounded Conductor Terminations. Each grounded
conductor shall terminate within the panelboard in an individual
terminal that is not also used for another conductor.
Exception: Grounded conductors of circuits with parallel
conductors shall be permitted to terminate in a single terminal
if the terminal is identified for connection of more
than one conductor."
There may/may not be a specific NEC Article concerning CBs, however, it's 1 conductor terminated per lug/screw. UNLESS the mfg instructions say otherwise. The only one that I a aware of for two (2) conductors terminating at one SP CB is Square D. (QO/QOB and others). The lugs are rated/listed for two (2) conductors.
BTW, in pic #2, the red conductor, lower left appears to being used to 'bond' the panel backbox, left lower stud??
Stay safe
