mm324: Am I the only one who thinks it's a little sad that a customer has to bring it to their attention, when the patch has been on another platform for over a month?
To whose attention?
GOG staff probably doesn't actively track each and every GOG game whether the publishers have released updates to them on some other service. They are most probably expecting publishers to provide the updates to GOG if such emerge, just like Valve also expects that the game publishers push the updates to Steam when needed (Valve doesn't actively track the update status of all Steam games either).
If you meant the publishers... I guess they usually know they haven't provided some update to e.g. GOG (and Humble Bundle, itch.io and whatever other stores there may be with their own delivery system), and they might react only when someone bugs them enough of it. Or maybe in some cases they have just forgotten to prepare and send the update to non-Steam services, I guess they are humans too and forget things.
Even if GOG (Galaxy) update system was fully automated and developers can push updates on their own, I am still expecting GOG versions to lack behind, and sometimes skip or completely miss Steam updates. Yeah, I guess the GOG community needs to be a bit vigilant and proactive about this too, unfortunately. At least as much as tipping GOG staff about missing updates they've detected, it is GOG's job then to convince the developer to release it also for the GOG version. (I wouldn't be surprised GOG staff decides to skip some intermediate updates, if they know there is another bigger update coming later anyway; and I personally am fine with that approach).