Again, I can only reply for RoW based Golfs.
As factory built and as shown on my wiring diagram on page 1 of this thread - F18 is connected to the Reversing camera (R189) and to the Rear lid handle release button (E234). Because E234 needs to operate when the ignition is OFF, the voltage supply must be T30! This is confirmed on the column called "Terminal" in my picture ("Terminal" is the "T" in T30).
Your last response suggests that you might have simply spliced the camera +12V supply into the pin#18 wire on the Quadlock connector without installing a separate fuse.
I'm not sure how familiar you are with electrical protection theory and I apologize if you already know this stuff - but it ain't good practice if you didn't use a separate fuse.
The problem is that the factory wire that's terminated on pin#18 (Quadlock) is protected by a 20 Amp fuse on the F12 slot. As shown on my wiring diagram, the factory fuse for the camera (on F18 slot) is 7.5 Amp.
If you haven't installed a separate fuse on your project, it means that 2.7 times (i.e. 20 divided by 7.5) more Amps will be allowed to flow into the camera module when a fault occurs. Because of electricity law, this means that over 7 times more power (power=Amp squared) will be allowed to be injected into the fault before the fuse blows! This ain't good protection design!!!
So, if you leave the +12V camera wire connected to pin#18 - install a separate 7.5 amp in-line fuse into the camera wire, please. And as I have said in a previous response - physically place the new fuse somewhere accessible!
With this arrangement, the battery supply for the camera +12V wire will contain 2 x fuses which are effectively connected in series; the 20 Amp fuse from F12 slot and the "downstream", new 7.5 Amp fuse. Good fuse protection practice (it's called "fuse grading") allows series connected fuses if the second fuse is no larger than half the rating of the first fuse. So, a 20 Amp/7.5 Amp series connection of fuses is OK
Hope this makes sense!!