I saw it too not sure why, but it's a bit annoying.
They went bust.
Hmmm.. worked for me earlier.. maybe the trick is to only post the part of the address before the '?'
So if I post " www.amazon.co.uk / dp / 1905102941 /" without spaces I get...
https://www.amazon.co.uk/dp/1905102941/
That work?

It's broken, it has been for ages, and it's already in the bug tracker. It looks like it's going to be a little while before it gets looked at though, it's pretty low down on the to-do list.
As a workaround, if you post using the LINK button in the editor rather than just pasting raw text it works.
As a rule of thumb, when posting links 99% of the time the information after the ? is irrelevant bobbins and can be removed.
The reason you've probably not noticed either of these things till now is because I often clean then up manually when I see them.
