Wing forums have noted the issue,, Several different theories. Seem like warming the bike to the C line is (almost) a 'universal fix'

Some object to having to do so as they don't have to do it in their car. I understand. I can also adapt.

Some hit the button and then 'gear up',,, Might be all it takes to avoid the issue.

Some have said the NGK plugs help over the Denso's. Hard to 'prove' anything. (I like Iridiums )