For example, clicking the first image in this post and then clicking the right arrow to go to the next image results in seeing an image of cat fur from another post further down.
Now clicking back, expecting to go back to the originally opened one...nope! the other cat fur image.
Clicking several times forward and then going backwards does not reverse the same in a mirrored fashion. So far have not found any logic.
Using Firefox 112.0.1 (64-bit) on up to date Windows 10.