[Agda] Why is refine not working right with "_,_"?

[Samuel Bronson]

For instance, if I start with:

×-≃ (≃-≈ xy)    (≃-≈ xy')   = ≃-≈ ({!_,_ !})

and type C-c C-r, I get:

×-≃ (≃-≈ xy)    (≃-≈ xy')   = ≃-≈ ({? , {! !})

where the question mark is not picked up by the emacs mode as a hole
to put more code in...