Instants Spells Vs antimagic Fiel

[DRAKHOX]

I Have a Question:

In my Last Rol Sesion Y put to my players a Iron Colossus whit Antimagicfield.

The Oracle try to heal the gunslinger inside the AMF, i tell her that it cant becuse AMF dont let them do it
"An antimagic field suppresses any spell or magical effect used within, brought into, or cast into the area, but does not dispel it. Time spent within an antimagic field counts against the suppressed spell’s duration."

But they told me that spells what have "Casting Time: 1 immediate action" Like Acid Orb and "Duration:Instantaneous" like Heal spell are not afected by the AMF

This is true or not??

[Lathiira]

Nope. Instantaneous spells can't form within the field, and the casting time is irrelevant. It's 'antimagic field', not 'antiSLOWmagic field'. Magic is magic to it, regardless.