NM caused the change. Their instructors bitched to the Gov or someone high up. NM residents were getting UT NR permits to carry in NM.
It wasn't just NM. When the law change was proposed I kept a close eye on the hearings and debates in UT. There were several States making the same noise about the UT permit. Texas and PA were among them. Representatives from several States testified that if UT could not or would not make changes that they would be forced to drop reciprocity with UT.
Florida had the same type of push and it resulted in Florida requiring live fire. NM held reciprocity with FL because of this change.