When the 250 and 300 HPDI motors first hit the water, there were a number of issues with them. The problems persisted until Yamaha released updates to both the hardware and the software before the issues were finally fixed.
Unfortunately, even though the motors were sorted out and ran well after the updates, the perception about them being unreliable stuck like gum to the bottom of a shoe... and that perception, however undeserved, remains today.
It is unfortunate because the HPDI design is a good one. Heck, the 200 hp HPDI is one of the best that the company ever produced.
Today... it's all about the 4-strokes. :roll: