Yup, exactly. I don't know how they made it so flaky, but it's flaky every single time. (To some extent, I think it's bootloader-related issues; not a hardware or protocol problem, but a quirk of the bootloaders floating around.)

Once you get Micropython or Circuit Python loaded, it is pretty great. I think if I were teaching someone programming for the first time, that's the platform I'd use. (But every time I try, they say they want to learn React, try doing so for a week, and then give up on programming for good. You've gotta crawl before you can walk!)