Advice anyone????? :)

So the grinder at this new cafe I’m working at has been a pain in the arse.

I can’t seem like to set up the ground so that the colour turns yellow and pale at around 25-30 seconds. It takes like 40 seconds or more! And the taste is very very bitter at 40 seconds. But everything else seems to Ben correct.

Here’s a vid of a shot being poured
https://youtu.be/yFLrx67Q1rA

Here are the details of the current settings

Double shot powder weight: 20g
Espresso liquid in 29 seconds: 55ml
Machine temp: 125 degrees 
Machine pressure: 12.5 bar