Follow-up to Non-expanding here-documents inside command substitution

[Kevin Grigorenko]

On February 11th 2017, there was a discussion on the topic of 
"Non-expanding here-documents inside command substitution are subject to 
newline joining" where it was confirmed that Bash contains a bug. Two 
questions:

1. Is there a plan to fix this or should a patch be submitted?
2. Regarding the response:
> [POSIX] is not necessarily ambiguous, but it does require close
> reading.

Can you please explain how it was concluded that it's a bug based on the 
specification?

Thank you

--
Kevin G