This happens both in studio and online. LineHandleAdornments are not rendered at most angles, and are often completely invisible. Here’s an example of me moving my camera around a grid of LineHandleAdornments.
I really want to use LineHandleAdornments in my game, but this render glitch has been happening for at least 3 months now.
You should check the Studio version. If it’s not 276 then you should remove it and manually update - I’ve seen Studio on OSX not getting automatically updated for some reason sometimes.
Also do note that the fix affected all mobile platforms as well and will take a bit of time to propagate to all of them, so you may still see this issue on mobile for a week or two.