Homeguard for teemo

it's a bug from a long time ago, in all patches, including 5.14. When i play with TEEMO, and upgrade sorcerer's shoes to homeguard, not always you get the speed buff when being out of combat for 6 seconds and leaving base. i mean, when you buy them, you got it. then, when u die or back to base, maybe you get it or maybe not. or maybe it boost you 2 or 3 secs, and then no more.

anyone else is having this issue?

Thank you.