Let’s come back to the point at issue

[AlexAD]

Hello,

In the sentence, 'Let’s come back to the point at issue' I don't quite understand why no determiner is used before the issue. Could you explain why? The second question would be whether the at can be replaced with 'of'.

Your answers are really appreciated

Thanks in advance

Alex.

[Rover_KE]

'At issue' is a set phrase meaning 'under discussion'.

Rover