What is the issue here? UID is already in iTIP for VFREEBUSY/REQUEST, REPLY.
A COUNTER method is not needed for VFREEBUSY, as this workflow is a simple REQUEST (e.g., when are you busy within this window) and REPLY (e.g., here is my current busy time for this date-time window).
IMO, this issue is moot. It should be withdrawn from the list.
-- Frank