Rainbow Six Siege: No ETA on Fix for Purchase Issues

Update: Ubisoft has informed IGN that the issues are now fixed. We have confirmed that the problem appears to be gone on PS4, but haven't yet verified that on other platforms.
Original: Rainbow Six Siege players on multiple platforms are currently unable to spend in-game currency on new items or operators, and Ubisoft doesn't know when the issue will be fixed.
Reports of the problem - which sees the game failing to complete purchases with either earned currency Renown or paid-for R6 Credits