When Gillespie stands up to greet the new arrival of LuAnn, his shirt has liquid spilled all over it, there is no explanation of why.
Looking at the trees in the town square, you can see they all have leaves on them which are turning colors, indicating that this episode was filmed in the fall, not at Christmas time.
When the chief arrives at the Tibbs's house for the party it is snowing heavily, yet he has no snow on his clothes, nor are they even wet.