This is a generic, non-developer related macOS issue, but reporting here as well so it has more visibility since. It is an embarrassing bug that has not been fixed since the earliest versions of macOS Tahoe.
Issue description:
When Dock Magnification is enabled, the Dock Folder abruptly jumps approx. 10-15pixels down as the user moves the cursor after a brief pause).
Video about the issue (see the last second of the small video and observe the entire grid popup jump abruptly):
https://forums.macrumors.com/threads/macos-tahoe-26-4-release-candidate-now-available.2479503/post-34494643
Related FB: FB20761846 (opened in October, 2025)
The issue is easily reproducible and confirmed by many. The lack of this issue being fixed for so long is indicative in the eyes of many of the lack of attention to details in macOS Tahoe's Glass interface.