Startup delay on new T8 fixture
I replaced four four-lamp fixtures (ie sixteen tubes total) from old worn-out T12 to new T8 fixtures. They are all controlled by the same switch.
Two of the new T8 four-lamp fixtures come on immediately, a third one comes on with a slight delay, and the fourth one comes on with an even longer delay, perhaps 0.5 to 1.0 seconds. I'm surprised and disappointed since I thought I wouldn't have to worry about these issues after upgrading to T8 and electronic ballast.
Do these two slow fixtures have a defective ballast? Are they going to get worse in cold weather, or after a few years of use? Is there any effect on their reliability or power consumption? Or is this all within the normal range, and I'm just noticing the difference because I have four identical fixtures right next to each other?