Scrolling on PC in the garage appears to not adjust itself the longer the list gets; it appears to be a division / percentage, of the length of the list (I assume in pixels?).
Therefore what you end up with, is skipping entire rows when using the scroll wheel.
For example:
You have 10 bikes in garage, scroll wheel down once, half of the next item below appears.
You have 100 bikes in garage, scroll wheel down once, 4 entire items are scrolled.
Because only 3 bikes are visible, this means an entire bike was not visible to the user, which is the issue.