I think we are the ones who are confused by your dilemma. I know I am very interested in what finally fixes the issues you are seeing.
This is a tough question to answer on a forum like this so everybody starts grasping at straws.
You mentioned that you know other brewers who are not having this issue. Have you tried borrowing their brewing equipment and space? It might just rule out your processes and/or give you another set of data to apply to the hunt.
1) If you can take your ingredients and process and brew on a friends system and don't see a problem, then you know it is location or equipment (and you get some beer
2) After that, you could take your equipment and brew in different location. If that works then you know it is something around your home causing it.
3) If it follows you equipment then you might need to replace all your equipment in one shot (at least all the soft plastic). I would do the first brew session at the location away from home after replacing everything just to be sure it actually fixes the problem.
I really hesitate suggesting you have a buddy brew with their equipment at your place based on how persistent the problem seems to be. I wouldn't want to be the one who gives this gift to another brewer.
Good luck in your quest!