Three of us in our club have built paddlers in the last year. To a man, we all wish we had added to our models draft. Each model when tested was too twitchy, and very unstable in turns.
2 of us have re-made the superstructures ultra light, and ballasted the models to the top of the waterlines, the other has been shelved for the moment.
Naturally not all paddlers suffer this way, some are fine, but it is not uncommon. We found out too late.
Which paddler are you thinking of?