Hi Eren, thanks for your post.
1) It can be useful to start at 18V and run it this way for 2 weeks but mainly to reduce noise, it should still work. For the first two weeks parts are seating and wearing in.
2-3) My apologies for these issues, believe it or not, the 6206 is entirely hand made, it is one of the most extensive hand labor products in our range. It starts with a 3165/9002 skimmer body being modified and a 6055 being modified and the parts glued together, the sides are sawn off and everything is glued and hand fitted. This does introduce a high chance of small cosmetic blemishes (glue blobs, deformation from the solvents in the glue), in general though they should function properly, we do test everything before it leaves the factory except the power supply. I have seen these issues before and I assume that heat may be a cause, perhaps the plastic weakened by the solvent is more likely to deflect from heat. Anecdotally I have more of these complaints in the summer. You are correct that with some patience and manipulation it can usually be repaired. It may also be that the solvent is not completely dry and from laying on its side there is further deflection.