The presence of an apostrophe followed by a non-whitespace character breaks adoc's link detection.
https://github.com/bbatsov/adoc-mode/issues/new[foo bar] OK
https://github.com/bbatsov/adoc-mode/issues/new[foo' bar] OK
https://github.com/bbatsov/adoc-mode/issues/new[foo's bar] broken!
Screenshot:

The presence of an apostrophe followed by a non-whitespace character breaks adoc's link detection.
Screenshot:
