Clutch pedal "wandering"

Best way to explain this is: Most times when I get in my car the clutch pedal has a good hard feel to it when I push it down, and it grips really well. But sometimes the pedal feels weak and goes down with ease, and it doesn't grip as well causing the clutch to slip when shifting from redline.

My first thought would be there's air in the lines somewhere, but its so random I would think could be something else?? B/C if there's air it would just be weak all the time, correct? Soo maybe air in the master? Second thought would be the pedal adjustment jamnut thing is loose. idk, you guys tell me!

You slave or clutch master cylinder could be going.