Is it possible there is HDCP stuff within the broadcast
Not according to my understanding, but I suppose "never say never".
As far as I know, HDCP is confined to establishing the capabilities of the receiving end of a HDMI link (or I suppose potentially any other digital link with a limited return channel), and is implemented locally between the transmit and receive chips. If the receive end does not complete a cryptographic handshake when the link is first established (or re-established if it is broken), the transmit end is not authorised to output high-definition content. The receive end is only licensed with the appropriate crypto key if it is certified as incapable of recording HiDef content received from the HDMI.
There is a compromise in the Humax implementation, in that if the handshake does not complete it kills the whole HDMI -not just for HiDef.
Now, just speculating, but IIRC there is a protection mechanism built into DVD/Blu-ray players which is supposed to revoke the DRM capability of a unit when the industry 'broadcasts' a list of players that have been cracked - the broadcast mechanism being the discs themselves (contained within the non-content areas of each disk published after that date).
Is there some similar revocation mechanism in TV broadcasts? I doubt it. It is the Sonys and Disneys of this world with an axe to grind over content piracy, not public-service broadcasters (who are already putting the content out to all and sundry).
or content that is 'new' and causing some issues with older equipment?
That would cause a systematic problem and we would all see the same thing at the same time (or at least, those of us with "older equipment"). We have seen oddities with the data received in the Freeview streams which resulted in unplayable recordings for example, but these were systematic.