Hi Skunker, I had the exact same problem with my Otos, just opposite ears as you.
Any kind of talking or yawning, but especially chewing, and within a minute or two it would walk out 2 or 3mm. Very frustrating, having to re-seat it constantly, all day long.
I feel pretty confident that my audi made really good molds of my ears the first time around, so when I did complain about it, they sent them back to be “bulked up” a little. The first time was good for the right ear, but a second time was needed for the left. I do believe, they have slightly altered a taper on the left one, the second time. If I go a full 24 hours without wearing the aid (which rarely to never happens anymore), I do have to take a minute or two to slowly work the aid into my ear. I wouldn’t call it a “tight” fit, but definitely snug.
I know it’s a pain to have to deal with. My audi and her staff are extremely friendly and eager to please, so I never felt bad about having them re- and then re- re- do it (not to mention the fact that Starkey had to replace the left one twice, since it just completely and unceremoniously died and gave up the ghost, two times). I just encourage you to keep after it until you’re happy, or until someone shows you definitively why it can’t be done properly.