Similar to its behaviour in a turning quickstop to the right where you had to use left cyclic to stop it rolling in any further and even more left cyclic to get it to roll out again.
All down to the odd pitch-roll coupling effects most have seen on the Lynx - and possibly down to a combination of the high AoA that the retreating side of the disc can operate at (thanks to Berp blades) and the high effective hinge offset that gives such excellent roll and pitch response.
Noticed a similar thing - but the other way - on an Airbus helo during an airtest.