Try taking longer slow pulls. Bad technique can increase the tendency to "flood". Also low fluid level decreases the vacuum that forms inside and fights leaking. 100% PG fluid may be too thin and 100% VG too thick. Floods and leaks can also be caused by heat such as leaving it in a hot car, or the unit warming back up after being cold, either way the fluid expands.
Once a coil floods, it will tend to keep doing so, try blowing through the mouthpiece of the clearo with some paper to catch the fluid coming out the other end, also can reduce the excess fluid by turning the vape upside down so no new fluid reaches the coil and running it.
Theses designs have the little "chimney" coming out of the coil core which is actually brilliant. A small amount of fluid spitting and condensation in the mouthpiece tube is normal, and the tiny space between the chimney and surrounding tube helps trap it. This should be cleaned off when refilling to start it over. But obviously this can't deal with a lot of fluid. I've only had 1-3 defective new coil units in 6 months, though every once in a while when they get old they'll leak too. With the mini Protank see if it has actual Kanger coils (looks like one in the top pic, but I can't tell if its a clone) -- the base of the core is printed with their resistance rating -- these tend to be better.
