Cold damage?

[ladybug15]

I have a couple of Phals that are showing some odd patterns on leaves, and I am wondering if it is from cold damage. Both of these plants were in a bay window during a cold snap several months ago. We keep our house pretty cool at night (62 degrees), but I am assuming that it got much colder than that next to the window.
The first pic almost looks like mite damage, but I looked at it under magnification and saw nothing. It does appear to be on all of the leaves of both plants, with the bottom leaves being just slightly more yellow.
For those of you with more experience, do you thing it may be cold damage, or possibly a virus of some sort?