We seem to have yet another new comic reading interface this week. In this new interface, when I position my mouse pointer over the episode list in the main, lower part of the new right-hand column on the page, the page's overall scroll bar, on the very right side of the browser window, suddenly disappears, causing the entire contents of the browser window, comic and all, to expand into the new space left by the scroll bar's disappearance, abruptly shifting things to the right by that 40 pixels or whatever it is.
When I move the mouse off the episode list, the full window's scroll bar re-appears, causing everything to shift back.
This occurs in both Chrome and Firefox on Windows 10. In Chrome, I cleared browsing data, but the problem still occurred.