Can no longer add friends on more than one region/server

I play Wild Hearthstone semi-competitively, and—like many other competitive Wild players in this small community—I play the format on three servers (NA/EU/APAC).

In the past, I had been able to add friends separately on each server without issue. For context, I have 115 friends on NA, 24 on EU, and 17 on APAC, and some people are on my friends list for 1, 2, or even all 3 regions.

However, there is a recent bug (past few months) which prevents players from being able to add a friend on multiple servers: when I try to add a friend on a second or third server/region, I now receive the error message “This person is already your friend”, and am unable to add them. Most recently, I could not add a player on NA who I am already friends with on EU—I contacted this person outside of the game, and they too were unable to add me on the Americas region.

This bug affects BOTH the BNet Desktop App AND the Hearthstone in-game App.

I have tried logging out/re-logging into different regions, I have tried manually adding the friends in both Apps (BNet/Hearthstone), and I have even tried adding these friends as my “last opponent” after playing against them on the Hearthstone ranked ladder. Nothing works anymore, and there seems to no longer be a way to add a friend on multiple servers. Please help!