I downloaded my iPhone 5 SE images into Lightroom CC as usual, but all of them came in as .MOV, not the JPG images they were originally. I checked my phone, then my general computer download. There in the computer were both the JPGs and MOV images. I didn't set the phone for movies on these images, but there they all are, about 20 of them taken over 2 weeks imported today as .MOV in Lightroom. What's with this? Anyone else have this happen?
Is there any chance that your iPhone is set to take pictures as Live Photos? If it is, every photo taken with that setting will import with both a preview .JPG file and a 3-second .MOV file. If this is the cause you should be able to confirm it wth a test. Take a few iPhone photos wth Live Photos on, and a few more with Live Photos off, and transfer them into Lightroom. If the pictures with Live Photos off are normal and the pictures with Live Photos on all import with 3-second .MOV videos, then that was the cause. In the future you'd want to make sure Live Photos is turned off on your iPhone.
This happened to a friend of mine; she took hundreds of iPhone photos on a vacation and did not realize it had been set to Live Photos most of the time, and ended up with hundreds of 3-second videos.