I love my Holy trainer V3 Nano cage and I have had a V2 and worn it long term off and on for the last couple years. The fit is great because I am a grower not a shower, and in normal conditions there is no discomfort and everything 'hangs' balanced. However whenever I get aroused or cold, one testicle will ride up very high (almost above the 'shaft' of the cage) and the other one will tuck under the 'shaft.' There is not any discomfort at all with this, but i want to make sure that there is not something to be concerned about.
So long as when your cage is off your testicles are normal without lumps you should be fine. Mine ride up all uneven too. This is actually very normal for men as one testicle will naturally hang lower than the other so they can sit more naturally to gravity.
When it's cold, testicles seek shelter. As long as you are not in pain I don't think it should be an issue.