When the craft is flying “normally” the Motor 3 is at lower output than the others, Motor 1 and 2 are at higher output. Motor 4 is average. To me this indicates a weight imbalance, heavier towards motor 4. Most importantly it indicates a yaw bias, the CCW motors are working harder to counteract some phsyical issue like twisted motor mount or twisted arms.
When the trouble starts you see Motors 3 and 4 go to high output and Motor 1 goes to almost nothing.
So it’s like whatever was causing the original yaw bias suddenly slipped (twisted motor mount?) and started causing a yaw bias in the opposite direction.
It really helps to get the motor mounts perfectly aligned so all props are on the same plane.
Also check physical weight balance/COG before each flight.