The reader-images class is still col-auto instead of col, which means for small images (like this) you can only click to the next page within the image height.
Not really a fan of the black line on the right side.
If anyone else feels the same:
.reader.layout-horizontal.hide-sidebar .reader-controls-wrapper { border-left: none; }
@andriod15 Does the tampermonkey icon show a red [1] while on the page? I just tried in chrome and it seemed ok, might depend on the theme you're using?