Swiss format matchmaking issue

[Laytonian]

I've just finished playing a Splendor tournament (One-day Tournaments • Splendor 6h30) which adopted a 13-round Swiss format. The trouble was that in the final 5 rounds there were only 6 players remaining, and three players got matched together in 5 straight rounds. It clearly violated the "
Try to prevent same players to be opponents twice" player pairing policy.

Anyone could enlighten me why did it happen? Thanks a lot!

[Mathew5000]

I've just finished playing a Splendor tournament (One-day Tournaments • Splendor 6h30) which adopted a 13-round Swiss format. The trouble was that in the final 5 rounds there were only 6 players remaining, and three players got matched together in 5 straight rounds. It clearly violated the "
Try to prevent same players to be opponents twice" player pairing policy.

Anyone could enlighten me why did it happen? Thanks a lot!

Short answer: It's a bug. Please vote here, to increase priority for this bug to be fixed: https://boardgamearena.com/bug?id=56504

Some further discussion in the forums on this topic:
viewtopic.php?p=113514
viewtopic.php?p=124131