Im 3 days late but if you are doing all bosses runs then there is a known crash that happens, for this you should check out using the crash fix, found here: https://wiki.speedsouls.com/darksouls3:Crash_Fix
Would be helpful if you posted a video of what you are doing. I'm going to assume you are doing teardrop and it sounds like you might have hit a deathcam. When this happens your controls switch over to only being able move forward and turn either left or right.
Try to make a note of where this camera switch happens and avoid those areas.
But really, just upload a video of what you need help with so we can be of better help to you.
You are still welcome to submit glitchless runs to whatever category you end up running. It's always nice to have runs to share with the next person who comes along wondering about glitchless speedruns.