Not getting progress buffs

Hi! My first time using this forum so please bear with me, Posting on behalf of my duo here and hoping you guys might have some advice or help.

We’ve noticed whilst playing that despite doing the same matches my duo isn’t getting the positive buffs that come with win streaks or unexpected wins ect that I am.

For example we’ll go on a win streak and I’ll get that nice little green arrow and they simply wont. At all. For anything. They’ve literally never seen over 19% progress in their rank climb.

We’ve been tracking their scores and stats to see if it’s a case of gameplay but even when we both get the exact same number of wins or losses they get nothing I do.

We contacted support and got a generic message back saying that they won’t do anything because we’re on console and to contact Sony who said it’s an in game issue and to contact blizzard. Super.

If anyone has encountered this issue or might know why any help is appreciated, thank you!