your link shows a \ before each underscore in the visible text for me in both comments, like this https://en.wikipedia.org/wiki/File:Blue_stop_sign_-_hawaii_-_oct_2015.jpg and hovering or clicking the link replaces that \ with %5C, so the entire thing tries linking to https://en.wikipedia.org/wiki/File:Blue%5C_stop%5C_sign%5C_-%5C_hawaii%5C_-%5C_oct%5C_2015.jpg. clicking ‘source’ on those comments shows just the \ before each underscore
no idea what’s causing it, super weird to have the same bug messing with links that reddit does