I’m going to attempt a solution. Had a similar problem, couldn’t fix it for hours on hours.
It turned out that there is a variable called “JumpMaxHoldTime”. Personally i use C++, but this was my problem.
This is an old question, but im posting because everytime i googled my problem this question came up.
(Mine was wall jumping)
Hopefully this helps.
Side note! if you do change this variable then this enables infinite jump so an if statement that works off a jump counter is recommended.