Gorog boss fight glitch, need help

[Human Required]

During the first phase of the fight, when it tells me to mash his restraint chains back, no matter how quickly I mash, Starkiller's animations won't speed up to press the chain back in. No matter what I do, Starkiller won't do enough force pushes fast enough; it's definitely a bug since I played it on consoles and it worked fine. Can anyone help?