What you are seeing is blendspace typical.
The blendspace merges animations between pose A and Pose B at the given frame.
This often resuts in hops, stutter, or other wierd behaviour when the animations aren’t properly crafted to be within a blendspace.
For instance, if you start each animation on the opposite foot between run and walk, your blendspace will work. If both start on the same leg, then you get a hop like behaviour when transitioning speeds.
Sync markers are one way to cure the issue.
But their setup is a bit complex if the animations aren’t your own.
Using stuff out of the Paragon characters you have that as a pre-set.
If anyone stubles on here and has to set things up from scratch:
Cut up some 1 frame poses to test blendspaces with so you understand their behaviour.
The rough spots are always at the 50% blend value; this is where the produced pose is fully interpolated by the engine instead of being an actual animation.