how opening multiple chests at once works

if anyone has ever held 2 loot chests in their inventory at once (ether because you forgot the previous one was there or however you did it) you might notice that there is an option.

the other day i had 2 chest by chance and opened them both at the same time i ended up only getting Sea Hunter Aatrox from two chest's.

my guess is that one of two things happened:

1. loot box system is weighted, and when you open multiple chests you increase your chances at getting better rewards. this seems unlikely however considering Sea Hunter Aatrox is only a 750 RP skin however if i just got unlucky with both chests it is possible. however if this is the case i feel like it should be made obvious that it is improving your quality not opening multiple chests (as it makes it out to be), as right not it seems like your getting all your rewards and showing them at one time.

2. bug/error causing only one chest to open. this seems like the most likely option as it seems unlikely that this feature would go unmentioned and be misleading if #1 was true. if this is the case this should be fixed so that players who strive mainly off in game achievement in order to get loot boxes OR players who spent money on loot boxes don't have their time/money washed down the drain.

note: i dont know how this works with other loot such as level up rewards only about chests gained from RP and S ranks