Modified and Spread Duration-Need some help in understanding a topic

Can someone explain to me why modified duration lower than spread duration for floating rate bonds? I don’t have anyone who can help me out and I don’t understand the reasoning/logic behind this.

They should be the same (or, at least, extremely close to each other).

Effective duration for floaters should be shorter than modified (or spread duration).

Where did you see that modified duration is shorter than spread duration (for floaters)?