[GAMEPLAY] Shop undo button bugs if Brand dies during his ulti and buys a duplicate item by accident

Played Brand jungle with Spirit Fire skin and used Dark Harvet runes with Inspiration as secondary tree. The shop's undo button wouldn't let me undo an accidental duplicate buy while I was dead.

Looked as though the shop wouldn't let me undo a buy that I made because I already had an exact copy of the same item in my inventory so I wound up with 2 haunting guises by accident and wanted to undo the second haunting guise buy but the undo button wouldn't let me. I'd bought the first haunting guise some time earlier in the game and left the shop and hadn't gotten to go back before my death. When I finally died, I forgot I'd bought a haunting guise already so I wound up with 2 haunting guises, a jungle item, and sorc's shoes in my inventory (a total of 4 items) and the "Undo" button bugged out and wouldn't let me undo the buy. I had to sell the 2nd haunting guise as a result.

Steps Prior:

1. Teemo flashed and killed me with Blind Dart(Q) and an Auto-attack in the topside river.

2. I was able to cast my ultimate (Pyroclasm), but died during the casting animation. It hit Teemo once and bounced to scuttle crab, he was out of range for another bounce (he walked topside of the river to avoid scuttle and thus another bounce).

3)When I died, I had 3 items, a fully completed stalker's blade-runic echoes (blue smite), a haunting guise, and sorc's shoes in my inventory already. My Flash was on cooldown. Blue smite was still up with one charge. I was level 11.

4. I bought a second haunting guise by accident while I was dead (I thought I hadn't bought it yet) and noticed I already had it as I bought it. I saw the "Undo" button bug out immediately and it wouldn't let me undo the buy. I guessed that maybe the game saw that I'd left the shop with a haunting guise once already much earlier so it wouldn't let me undo the second buy even though it was an accident and I was dead.

5. I waited until I respawned in case it let me undo the buy then, but it wouldn't so I was forced to sell the duplicate Haunting Guise instead.

6. I was able to replicate it in a custom game by getting executed to mid turret within a second of casting my ultimate (was able to successfully cast it, casting animation ended and I died while standing as Pyroclasm bounced in the minions). I bought full blue-smite item, haunting guise and sorc's shoes (any order when I did it) prior to the death.

I left the base and stayed out until I had 1500 gold for a 2nd haunting guise and then died in two separate situations: A) First, I tried replicating it by executing to bottom turret without casting my ultimate but I was able to undo the buy in this case.
B) Second, I executed myself to mid turret this time but I tried it with casting the ultimate before my death. The "Undo" button bugged out immediately (stopped my testing at this point since I got it to work).

Side note: I bought the 2nd haunting guise in both cases without buying any pieces of the 2nd Haunting Guise first so I'm not sure if buying pieces of it matters. I never casted any other abilities in the original case or the two testing cases either. Both 1st and 2nd attempts to replicate the bug were in the same game with a Garen bot on Beginner (so no issues with certain champions being in the game causes it).

7. Conclusion: It looks like casting Brand's ultimate and dying while the ultimate is out causes the bug where you can't undo a buy in the shop (it may only be exclusive to accidental duplicate item buys as well). It doesn't look like it matters if the casting animation is happening or not, it only looks like it matters that that the fireball from Pyroclasm is out during Brand's death and a buy is made soon after. I made sure I had the same items, not sure if that changes it. My champion level, summoner spells, and skin were different when I tested it (flash was up, I was level 13, and I used Zombie brand skin instead of spirit fire). The shop wouldn't let me undo the duplicate buy in the event that Brand died while Pyroclasm was out. I don't know if it's exclusive to Haunting Guise or if this happens with other duplicate items too (like buying a ruby crystal, leaving base, dying during the ultimate, and then buying a 2nd ruby crystal).

Looks like the overall conditions are as follows though:

1. Buy item, leave spawn (only tested buying haunting guise as 3rd and 4th item, could be with other items too)
2. Cast Pyroclasm and die soon after while it's out
3. Accidentally buy a duplicate item which triggers the "undo" to not work in the shop. Possible that it only works with Haunting Guise, not sure since it's untested.

Additional note (conditions I don't know): A) I don't know if it only works when buying the 2nd haunting guise without buying the pieces first. B) Not sure if it's exclusive to Brand needing to have 3 items first and then buying the duplicate item as a 4th triggers it (didn't test if it occurs with it being a duplicate buy as a 2nd, 5th, or 6th item). C) Not sure if it's exclusive to just buying Haunting Guise twice or if it happens with other items (i.e. buying ruby crystal and leaving base, casting ulti and dying while Pyroclasm's out, then buying a duplicate ruby crystal by accident). D) Not sure if it's exclusive to Brand having Smite-Dark Harvest-inspiration combo either E) Not sure if he has to have the same 3 items first (completed blue-smite AP item, Sorc's and a haunting guise) or if the items don't matter and accidentally buying duplicate item at any stage is all that matters (i.e. having 2 fiendish codex's or 2 oblivion orbs).
F) Not sure if the bug still exists if you try to make the buy after the ultimate fizzles or if you wait until you respawn.

Hope this helps, good luck! Sorry no video footage!