Clutch Pedal Losing Pressure

[IM-32-FK]

Over a few months i would bleed the slave cylinder regularly and the clutch pedal would be fine, but now its starting to play up again. The clutch pedal is losing pressure when i initially start and drive the car but after about 15-20 minutes of driving it goes back to normal. What happens is the 'freeplay' on the pedal extends so you can push it down with one finger(maybe about 15cm) and it goes down quite a bit before the clutch actually engages and the pedal goes hard but after driving for like 20 minutes, the 'freeplay' on the clutch pedal shortens to maybe 5cm like how it always should be. I havent bleed it in over half a year at this point and im going to do it again, but does this sound normal to you? I shouldn't have to bleed the slave cylinder so often. Does this sound more like a problem with a worn throw out bearing?

Also i was going to ask, what is the point of bleeding the master clutch cylinder? when im bleeding my slave do i bleed the master cylinder to? Which one do i bleed first and what is the procedure of bleeding the master cylinder and how do i know when the master cylinder has been bled out good?

thanks

[Hadouken]

its a common n1 altia MC problem