I have a F18T8 GE aquarium tube that's like this. The trigger start ballasts can't start them because of the low OCV but they run fine off F20 preheat.
This lamp have krypton gas filling, which have higher ignition voltage than argon, so it can only start well on preheat or electronic ballasts.
Also: 5000K should looks as a pure white without hint of yellow or blue.
Also: 5000K should looks as a pure white without hint of yellow or blue.