Grade level

Does anybody know I was grade 2 for a long time and then all of a sudden it put me back to grade 1 and I have All the right credentials for grade 2 can anyone help me

There is a certain flight time and landings required in 90 days for you to keep your grade. It is on the requirements.
Use this as a reference.

To get back to grade two you need to meet the 90 day landing requirements.