Vehicle selection menu

not sure how to title it. I open vehicle selection menu, and scroll; my vehicle list always breaks around the halfway mark and tries to go back up, resulting in a vertical twitch, and softblocks any further downward selection. I used to ignore it because i can scroll fast enough to override the "wall", and attributed it to old/bad mods, however its been two years, all new mods, and a new installation of windows and I still have this issue. it only affects non-vanilla game and only as soon as a new car mod is added, but it doesnt care which car mod so I'm assuming its a bug with the scrolling system. why it is a problem enough for a report/discussion now is twofold: the wall has seemed to have gotten worse today, and I have found it makes vehicle selection via controller or keyboard impossible past the Gavrils. I HAVE to use my scroll wheel to get past it. As of right now i have a very heavy 400 mod load, however I see it even with only one mod. I have cleared cache, updated mods, etc and never had it disappear without total removal of all mods.
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I should also add: it only affects downward scrolling. there is no "wall" scrolling up from the bottom of the list