Matinee Markers can't be changed

I’m currently trying to use matinee to make a quick cutscene. However the green and red markers won’t allow me to move them. When I try to change the length of the matinee, they will both pop to the 0 marker and won’t allow anymore changes. The black scrubber will still move along the timeline, like normal. Is there a setting that I’ve somehow changed causing this to happen?