to be frank, quickly after purchase i experienced same problem, hot button and massive voltage drop with any atomizer tried , any
coils , Ti or Ktal from 0,3 to 1 ohm, any batts. i
vape 'mech' since 2012 and probably have more than 50 full set-up , 19 GG's and some widely more complicated than cybrillion, but i'v ended in beeing unable to find the problem and solve it. cleaned meticulously and rebuilt several times, with special care to the button ring, its own alignment and size of the orings, i bought a full set of new 'black' isolants and spring with no added benefit, my cybrillion finally didn't join the small 'holidays/travels
vaping fleet' and since stay as it is...
my two 23 tilemahos are back to JustGG with GG4's style cap and the other hybrided connection, i still use everyday my 22mm GG4's and my beloved esterigon500/tilemahos hybrid.