Blendspace stops smooth blending when using sync markers

I have a basic Walk-Run-Sprint 1D blendspace. This pertains to blending animations within the blendspace.

Animations without sync markers blend smoothly between two animations. Adding a sync marker “LeftFootDown” and “RightFootDown” in each animation causes the blend to behave improperly. There is minimal blending between animations except exactly halfway where it will abruptly switch to the next animation. The animations are now synced beautifully, but it is no longer blending.

My animations start with the right foot down first.

You can see the character suddenly start sprinting after I move the blend halfway.

I have the exact same problem, did you solve this?