Under discussion is something to be sneezed at (7)

I believe the answer is:

atissue

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'under discussion' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'is something to be sneezed at' is the wordplay.
I cannot really see how this works, but
'is' is present in the answer.
'at' is present in the answer.
The remaining letters 'sue' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...

Can you help me to learn more?

I've seen this clue in The Daily Express.

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