As you know, this forum offers insights into the experience of owners, renters etc. It is not legal advice.
With that in mind, have a look at the Strata Management Agency Agreement that your scheme signed with the managing agent. Look for where it mentions representing the OC at courts and tribunals and what it says about the matter.
In my experience in several schemes the agent is paid to attend court or tribunals and the OC (or SC more often), decides – before the matter is heard – that it’s best for the manager to attend rather than the SC executives. I have not come across a situation where an agent represents an OC (but does not consult them before hiking to court) and after the hearing demanding payment from the OC for his unadvertised attendance at court (even if it’s not required by the Strata Management Agency Agreement).