Inconsistent result with user function vs. primitive function

[Elias Mårtenson]

Consider the following two commands. I believe they are effectively
identical, but they return different results:

*      1 2 3 -.×⍨ 10 11 12*
4
*      1 2 3 {⍺-⍵}.×⍨ 10 11 12*
24

I tested on Dyalog, and there both versions return 24.

Regards.
Elias