[Agda] implicit lambda in Development Sep.16

[Sergei Meshveliani]

Dear Agda developers,

The fragment

  Prime∣split :  Set (α= ⊔ α)
  Prime∣split =  ∀ {p a b} → IsPrime p → p ∣ (a ∙ b) → p ∣ a ⊎ p ∣ b

  ...

  prime∣split-nz :  NZPack0.Prime∣split
  prime∣split-nz =  \ {p a b} → impl prime∣split {p} {a} {b}      -- * 
                    where
                    impl :  Prime∣split → NZPack0.Prime∣split
                    impl =  proj₁ Prime∣split←→Prime∣split-nz


is type-checked in Agda-2.5.1.1,

and Development Agda of September 16, 2016 reports

-----------
Found an implicit lambda where an explicit lambda was expected
when checking that the expression
λ {p} {a} {b} → impl prime∣split {p} {a} {b} has type
NZPack0.IsPrime .p →
(UpCommutativeMonoid.upMonoid *upCMon-NZ UpMonoid.∣ .p)
((*upCMon-NZ UpCommutativeMonoid.∙ .a) .b) →
(UpCommutativeMonoid.upMonoid *upCMon-NZ UpMonoid.∣ .p) .a ⊎
(UpCommutativeMonoid.upMonoid *upCMon-NZ UpMonoid.∣ .p) .b
-----------

If you can guess of what is this effect, then, please, inform me
(because I wonder, how to fix this).

Thanks,

------
Sergei