Previously Housetrained Dog Peeing and Pooping Inside?

I have a female Morky, a dog door, in a two story house where my bedroom and masterbath are upstairs. In the past she had peed or pooped occasionally in the house. She is peeing and pooping very often in the house now. She mostly does it in my master bath. Now she will go upstairs and pee or poop even during the day!

It can't be that she is too lazy to go out as she is much closer to the dog door downstairs. It is as though she is trying to annoy me or tell me something. She usually sleeps with me on the bed. But if she pees or poops in the bathroom, she will sleep under the bed as if she knows she is being bad.

She used to whine at night when she had to go out. She liked to be escorted to the dog door. I would give her a treat after she comes in thinking she would do better if encouraged with treats. Then she started asking very often to go out so she could get a treat. So sometimes I would just praise her and pet and love on her rather than give a treat. Next time she might go pee or poop in the bathroom. I think I have created a monster with the treats.
What to do?

By PSG