I have had this happen to me twice, once on this snot; the first time I was out shooting outside in winter and then entered a tropical conservatory. At the conservatory the lens was essentially opaque with condensation, I had to wait 20 minutes for the lens to warm up and the condensation to evaporate. That time I has a UV lens filter, so the condensation did not happen on the actual lens.

And thank you for your compliment on the photo, serendipity smiled upon me that day.

Cheers,
@kellyjanderson