I can't change the due date and time to tasks. It looks like it stuck on some 3:00am and that's all. I've tried changed it manually or with the help of Planyway Calendar power-up. But unfortunately for some reasons some of our tasks still stand as frozen. Sometimes I can change a day, for example for Sunday but suddenly it goes to Saturday and then stuck there. Some of them even lost few labels with a priority mark((
So I ask for any help 
I think these errors occur because of BigPicture power-up that we tried to install, but it was to slow, so we decided to unplug it.
Thank you!