I noticed that when I tried to link to an webarchive page in a forum post, the forum post editor apparently replace the second ":" with ":", and thus breaking the link.
This link should point to http://web.archive.org/web/20130807142126/http://www.samuriah.com/images/CementTileable03_Thumb.jpg (which weirdly works, if you copypaste it from elsewhere, maybe becasuse it's automaticly detected as an url)
1. I tested this both on Chrome 69.0.3497.92 (Official Build)(64-bit)(my main browser) and Firefox 56.0 (32-bit).
2. I tested it on Chrome with all extensions disabled
3. I tested it on Chrome after clearing my cache
Guess:Maybe the linking tool is assuming the second ":" is not part of an correct url, and converts it to html-code equivalent.
Other: Didn't find anything obviously similar on a quick web search
