The Stampede incompatibility

I use Rotgut triggered when adjoining flask is used. I wear the Stampede boots.
I notice no change in speed when Rotgut is triggered from the 40% speed increase or the Onslaught buff.
I notice the change when I use different boots but not when I use the Stampede.
Is there a reason for these movement buffs not working with those the Stampede?

Stampede sets your movespeed value to 150% of base and it cannot be modified in a positive or negative way.

ok thanks