While using 'Jump Boost' and 'Speed' potions effects the player looses a significant amount of forward momentum. This is less noticeable with level I and II speed, but it is present. It is a becomes more noticeable with a higher level speed effect.

Video link demonstrating issue.

Note the player has Speed III and Jump Boost. Their speed instantly reduces when they jump and the angle of their jump is steep. It is almost as though forward movement speed is set to walking when a player jumps with jump boost.

This feels somewhat unnatural, the angle of the jump should be shallower therefore covering more ground while under speed effects.