How does the bugged implementation of gifting affect friendship levels?

I understand there is a bug.

• Niantic Support
• Reddit/r/TheSilphRoad

I can't really describe the bug other than by saying that friendship levels aren't increasing as originally explained by Niantic.

But, given that bug, how are friendship levels actually affected by gift-giving/receiving?

I'm looking for a full description of how the buggy implementation works. That should include things like:

• What causes actual increases?
• Is this just a display-bug?
• To the extent that this is just a display-bug, what causes the display of one or both friends' levels to not reflect the actual increase?
• What causes an expected increase to not happen?
• What happens if you and a friend both send each other gifts on a day and both open them on that same day? Does the order matter?

The bug is no longer effecting the game, but I can put some information to explain here for people that are looking around.

The bug was that two friends would not have synced up friend levels at all times, and that comparing between accounts would show this difference. In actuality, this was just a display bug caused by the fact that the account of a gift giver would not update their friend level when the receiver opened the gift. Therefore, only one side of the friendship would show the increase, even though it would technically be in effect for both sides.

If both friends sent each other gifts and opened them on the same day, each friend would see the friendship level increase when they open the gift, but it would actually only amount to one increased level per day. The only real benefit would be that both friends would be up-to-date when they check the friendship level.