Car is leaning like it's gonna tip over

2013 Honda Crosstour 238,000 miles Every once in a while while I’m driving on the expressway, the car suddenly feels like it’s leaning heavily to the left, and it scares the crap out of me. I don’t mean that the steering simply pulls to the left. It actually feels like the whole car is tilting/rolling to the left. The sensation is strong enough that I instinctively lean my own body to the right, almost like I’m trying to balance the car out. When it happens, it genuinely feels like the car could tip over. I end up slowing down pretty drastically because the sensation becomes much less noticeable at lower speeds. The weird thing is that it’s intermittent. A few months ago I took it to a mechanic specifically because of this. They spent probably an hour and a half looking it over and also took it out for a test drive. They couldn’t find anything obviously wrong, and of course it didn’t do it while they were driving it. I honestly think they started wondering if it was all in my head. After that, it actually stopped happening for several months. Then last week it started doing it again, and it’s terrifying. Has anyone encountered something like this before? Any ideas of what it could be?