intro bots bug -- inventory filling out with giants belts??

i just got the mission for killing 200 champions as a team, so i decided to grind it out real quick using intro bots. so i pick dark harvest garen garen, go bot, proxy the first 3 waves, last hit the turret, get some kills, grab swiftness boots and deaths dance

i then run behind the enemy nexus and start racking up pentakills. i wandered in the fountain a couple times

at the end of the game, i realized i had WAY more hp than i should. i look in my inventory, and i have 4 giants belts that i never bought. i had not gone back to base ONCE since getting the deaths dance

i would provide a replay, but apparently you cant get replays for intro bots