How "Resilience - Building a Better You" Quest works, and how to complete it without trolling

I just played a duo queue ranked game with my brother, and when we aced the enemy team with baron and still had 3 alive, Varus (bro), Reksai, and Darius (me). My brother told me to b back and buy Morellos/IE to complete my quest.

My brother was just looking after me because he knows I never play mid, so the chances of me getting Morellos is unlikely (The only AP top I play is Vlad and it'll be a troll 3rd item at best to complete my quest). I do play adc here and there, but IE rushing isn't as popular as it used to be.

I told my brother, no, I don't wanna throw the game, and I'll help you push, but he insisted that he and Reksai could end because the death timers were long and they had baron.

I wanted to maybe push to the nexus, and as it was half health b back, but my brother gave me a false sense of security and I ended up b'ing in front of nexus towers.

So I used my baron empowered recall to b back and sell items to buy Morellos. As I was selling more items for IE, Reksai and my brother died while the nexus was exposed. Everyone pinged me and asked what the hell I was doing (rightfully so, except for my brother who was laughing his ass off) and I responded bluntly: "Buying Morellos." Reksai and LeBlanc were not too amused, while Nami found it funny.

I still hadn't bought IE at this point, and refunded all of my troll buys/sells and grouped up with my team again. I was really afraid of losing, and had we lost the game, I would've gifted everyone a skin as a sort of apology. Luckily, I got a good 4 man pull initiate winning us the last teamfight allowing us to easily ace and push the open nexus.

Of course, having trolled my team already, I thought, might as well massively troll and b again. I b'd again (still had baron empowered recall) and sold most of my items for Morellos and IE, thinking that I probably needed the items in my inventory at the end of the game.

As my link shows, I got credit for a Randuins I sold (twice) and did not have in my inventory at the end game screen, Morellos which I bought twice, refunding it once and having it in my inventory at the end game screen, but not IE, which I only bought at the end of the game and had in my inventory in the end game screen.

My theory is that you need to buy the item a minute or so before the game ends, otherwise you do not get credit for buying said item (to prevent b'ing back and buying items right before the game ends). Bizarrely, I think buying and refunding items counts which is why I got credit for Morellos. You do not need the item in your inventory at the end of the game, which is why I got credit for Randuins.

So, if you want to complete this quest without massively trolling like I did, when you have enough items to sell for Randuins/Morellos/IE, just sell all of your items, buy said item, then refund back to your normal build. As long as you do this a good few minutes before the end of the game, you should be good.

If I offended anyone with how I treated my team, I'm sorry, I know what I did was troll. Though it is no excuse I was a major part of us coming back into the game and was the only winning lane that I really shouldn't have won (Darius vs Jayce).

Hope this helps some of you in completing the quest and not trolling your teams!