webstrand of the cascading-style-sheets Discord has pointed me in the right direction!

The issue appears to have been with scroll anchoring! He linked this page on the topic, which mentions both a way to determine what element is being used as a scroll anchor. In this case I determined that the text was being used to scroll anchor.

Utilising the suggested overflow-anchor: none; CSS property upon the grid or the items has stopped the unexpected scrolling!