Yes, and I've only partially solved it.

If I highlight rather slowly, and without the pen at an angle (ie straight up) then I have a good shot of getting it to be accurate. The problem I usually have is that when I want to highlight starting at a beginning of the line, the end of the line before is also highlighted. At least I've figured out how to erase the highlighting now!

I have a charging issue, so I'm not using the device until I get that resolved, but I was also going to try re-calibrating the e-ink screen. My husband and I both use the device, and I'm left-handed while he's right-handed, so I don't know whether another fresh calibration might help. But, it's definitely my biggest complaint with the unit (other than the charging thing, which I'm working on!). After slowing down and taking great pains to be accurate, I usually don't have to try more than 2-3 times to highlight what I want.

I also have thought about (but haven't had a chance to experiment yet) using a jaggedy up and down motion to highlight more than one line at a time. I still have not yet figured out how to highlight more than a single line of text. (Not including extraneous text from other lines that gets highlighted by mistake.) Sometimes what you want to highlight will span across more than one line, and I don't want there to be 2 different table of content entries for it, ideally.

Thanks for bringing up this issue, because I keep meaning to post about it but have forgotten. I love everything else about the Journal, but the highlighting (and erasing of highlighting) has been a bit of a pain. I tend to take notes more than highlight, but I've started highlighting specifically to create a table of contents in the pdf, so I'd love it if someone has figured out how to do this more gracefully than I have managed to do it.