Hi there, I'm just getting round to processing some photo's from the weekend and came across this strange 'thing'

What's caused the purple distinct circle within the lift? It's not on any of the other pics from that day. click on photo for EXIF data...could it be flare due to uv filter on my kit lens?
Thanks for any advice
Joe
PS I know I need to straighten it and sort out the blown highlights but this really threw me.

What's caused the purple distinct circle within the lift? It's not on any of the other pics from that day. click on photo for EXIF data...could it be flare due to uv filter on my kit lens?
Thanks for any advice
Joe
PS I know I need to straighten it and sort out the blown highlights but this really threw me.