Here's an idea. I assume you have other tanks so this won't interfere with vaping any more than a drippy tank already. Maybe stop using it and just try out different wicking techniques. Leave it home/wherever, on a tank stand with some paper under it and try a different approach several times. Do a few unpowered puffs to make sure you're getting feeding into the juice holes. When you have one that does not leak over a day, pop it on your mod and vape at home with it. When it is trustworthy for a day or two, then start carrying it outside.
I say this only because you have several variables making it difficult to know where the problem is. It seem like it's OK in a drawer at work (probably lying on its side) but when mounted vertically on your mod, leaks. Then there was the issue of possibly leaking from leaving it the hot car for a bit. By keeping everything consistent you'll hopefully have better insight into the why here.
That's kind of close to how I set up new tanks myself. I just got a Squape clone yesterday which came with a very narrow deck for wicking, but for $2, I couldn't complain. First build, leak. Wash, rinse, dry, repeat. No leak. It is now sitting upright on a tissue and got through the night dry. I'll probably puff on it a bit this afternoon then back on paper. If it makes it a few days, then it can leave the house and enter regular rotation without worrying about it. If it kept leaking despite multiple builds, I'd know it was another problem and start going over o rings and all. I had this with a KF5 from FT. After days of it gushing juice no matter what I did, I finally sent it on a slow trip back to FT. There must have been something wrong in the machining I couldn't identify. Hopefully that's not the case here, but you have to work the problem through changing only one variable at a time to be sure.
Yeah, I think I'll build that and my second Bellus out tonight just for that reason.