Leaking 7135

I have build my own driver, running my FW for the OL/BLF challenge.
Unfortunately the main LED, connected to 8 AMC7135 current regulators and controlled by PWM from pin 5 is not behave as expected: It is illuminates constantly in low brightness and does not change level when I increase the PWM period. Connecting a simple 3mm LED directly to pin 5 behaves as expected.
I have already replaced all regulators with new chips and tested the circuit for short circuits.
Not sure if it is a HW or FW problem.
Any help would be appreciated since I have tried everything I can think of and was not able to solve this.

MCU is ATtiny13a
Code related to PWN is:
DDRB |= (1 << DDB0);
PRR &= ~(1<<PRTIM0);
TCCR0A = 0b10000001;
TCCR0B = 0b00000001;
OCR0A = 0;
OCR0A = 125;

Not sure if it is related to your problem but try to add a decoupling capacitor between pins 4 and 8

What is the base frequency of your PWM? Is it within the frequency response bandwidth of the 7135 (listed in the datasheet?)

Thanks YuvalS, I did not add it to the sketch but I am using a 0.1 capacitor and it did not solve the problem

Thanks kennybobby, I am using 1.2MHz. it is within the spec and I have even been previously used 4.9MHz successfully.

Apparently I had two defective regulators. after replacing the defective components everything works as expected