Are these new behaviors concerning or am I just being paranoid?

[Bogertophis]

...The handling thing happened like a couple years ago though, since my sister no longer works at that facility I haven't been there in a long while. And the last herp I handled was a couple of leopard geckos owned by a friend. Could she get something and appear normal for a while and then suddenly show signs of something contagious now? ...

Sure, you bet. Some things have a long incubation time (though probably not over a year?)- that's why keepers do long quarantines in the first place. So as not to put their entire collection at risk from one newly-acquired animal.