DestroyActor interrupts Delayed Setting of Max Walk Speed

Just trying to figure blueprints out! I followed along with this tutorial: Blueprint Quickshot: Pickup | 02 | v4.7 Tutorial Series | Unreal Engine - YouTube

At the end I decided to attempt to make the speed powerup only last for a certain number of seconds. I spent almost 2 hours trying to figure it out and ended up using Delays. i.e On Collision Max Walk Speed is set to 1500 and then a Delay is introduced for 5 seconds and then the max Walk Speed is set to 600.

The problem is that I still want to have the powerup actor destroyed. If I attempt to place the DestroyActor node anywhere in the blueprint - the Delay CEASES to function and Max Walk Speed is permanently set to 1500.

Two images are here:

Working Delay (DestroyActor is removed, powerup lasts 5 seconds): http://i.imgur.com/pZtAKty.jpg

Broken Delay (DestroyActor occurs BUT powerup is permanent): https://i.imgur.com/vqm7Yub.jpg

*Note I have tried placing DestroyActor everywhere in the sequence of nodes and the powerup continues to remain permanent i.e the Delay + Setting of movementspeed back to normal does not occurr

I am simply trying to get a better understanding of how blueprints work - so I am curious as to why the DestroyActor function interrupts the blueprint!