I’m getting a Security Centre RED Warning that the firmware isn’t up-to-date,
which clicks through to Control Panel, which showing the version running and confirms that no update is available.
I’m officially confused
Hi mate, there was a recent firmware release, which was subsequently pulled by QNAP for unknown reasons. The update notifications will be a little out-of-whack for a while. 
You’re on the latest firmware, so there’s nothing for you to-do.
I considered telling Security Centre to ignore this issue but I assume that’s not a one-off filter and it would ignore the same warning for future releases to…
Disabling security center would be a good thing to do (mostly bogus anyways)
Keep the NAS out of the web and you are golden 99%
Regarding the situation you encountered, this could indeed be related to adjustments in the latest firmware version available. We recommend that you try re-scan to see if the warning persists. Thank you!