What caused this world-class player' to respond inappropriately to her partner's transfer bids?
This looks like one of those tantrums that happen when both partners want to control the hand.  The argument gets out of hand. Both partners think they know what is best and fail to yield until it is way to late.  I wonder if south thought "take that then" when she placed the last pass on the table.

I hate to admit it but I've been there done that.  Please never again.

I suppose it is possible that south thought the the redoubles showed hearts but i strongly doubt it.