Item's AttributeModifier Speed does not work correctly

I gave a bow the Attribute Modifier Speed with a negativ/positiv value.

What I expected to happen was...:
Become faster or slower while holding it

What actually happened was...:
I got the slowness/speed only for a moment when I selected the item

Steps to Reproduce:
1. Give yourselfe a Bow with a Speed AttrivuteModifier tag via commandblock
2. Hold the Bow in your hotbar or off-hand
3. You will only get the Attribute effect for a very short moment