I tried every mode imaginable, and it was always there
The only thing that I can think which might make a difference is I have a full Manual lens on.
But it's highly unlikely that this could make any real difference
Try taking out the batteries for the night, and plug them back in in the morning.
It might just re-set it's self
If it doesn't it's time to contact Pentax.
I don't know if they have a customer help line.
Edit, if it works can you please post a photo of your Marco Studio.
I'm 1/2 thinking of making a light box or something else along those lines, and your setup might be just the ticket.