This is a standardized problem pattern distilled from one OEM bulletin, not a universal explanation for every misfire. The entry condition is rough running on initial start-up after a cold soak and/or one or more DTCs from P0300 through P0306 on an applicable 2010–2017 Lexus RX 450h.
The bulletin requires normal misfire diagnosis first. Only when the mechanical engine, engine-control, ignition and fuel-supply checks reveal no concern does it direct a visual inspection of the fuel-injector tips. If the entry conditions or debris finding are absent, the bulletin does not apply and diagnosis must continue with the appropriate repair information.