I'm not able to find the occurrence you refer to in the man page for bash from Ubuntu or even directly from Upstream so I'm going to ask for you to provide a screenshot or pastebin from terminal so we can confirm this because as of right now I do not believe this is a valid bug.
I'm not able to find the occurrence you refer to in the man page for bash from Ubuntu or even directly from Upstream so I'm going to ask for you to provide a screenshot or pastebin from terminal so we can confirm this because as of right now I do not believe this is a valid bug.