
I also just checked the Shrink skill which has similar settings to Cold Touch, and that one can be activated on the Field just fine.
EDIT: I've also tried letting a different Actor use the Skill and having the original Actor use the Shrink Skill. The Shrink Skill could still be used in the Field, so it's not a problem with the original Actor. The Skill could not be used by other Actors on the Field too, so it must be a problem with the Skill itself.
EDIT 2: I've also just tried changing the switch, ticking the Battle checkbox, changing the description, changing the Skill name, changing the sound effect, changing the MP Cost, and re-creating the Skill in another slot. None of that helped.
EDIT 3: I copy-pasted Shrink over Cold Touch and changed things accordingly so now Cold Touch works! Problem has been solved