Which parkour? If its Build Battle then many players experience a similar issue, just change to an older update unless you're going for a top-10 time or lower because then you lose time playing on older updates in cp1

Sorry I'm so late to read this. Your best advice is to try a different version. (as SummerPi said). Most accounts respond differently, allowing some versions to work and some not to. Luckily 1.19 is coming out which gives you an opportunity to get rid of the glitch. I have this on many of my versions which is why I've been reluctant to upload a Bedwars record, so it would be cool to have Hypixel fix this as it is a lag spike on their side.