Why are these different?

A little background first.

I was shooting indoors at a pottery studio with some friends. I was borrowing a 24-70mm F/2.8L from one of them (wow it was NICE).

Anyway, I was shooting fully manual, had my WB set to fluorescent, was shooting RAW, didn't move in between shots, didn't change anything between shots, and in a few instances as I will show below, I got very different color temperature on shots taken within a few seconds of each other. There were 8 to 10 of the long tubular fluorescent lights in the working area.

These shots were straight from my RAW files, exported via Canon DPP with no changes. Full exif data is intact.

Fluorescent lights are not constant. They cycle. You took your pictures at different moments in the cycle. I forget how fast they cycle (maybe 60 times a second). If you have a shutter speed 1/60 or less you will go through the whole cycle and your pictures will be more consistent. The images you posted were 1/200 and 1/160 so you caught very small fractions of the cycle.

I'm sure someone else will chime in with more specifics.

I was suspecting that something like that would be the case.

It was just a little strange because I took about 40 shots while I was there, and there were 3 or 4 instances like the ones I showed where the shots had a yellowish tint, but everything else seemed to be acceptable to me, where the color balance was similar to the last image posted above.

When shooting in florescent light (or any lighting that's powered by line current), set the shutter speed to 1/120 (or 1/125), 1/60 or any thing slower and you'll be fine.

Fluorescent lighting is a non-constant light source as opposed to tungsten..Fluorescent lighting "pulses" and changes colour temperature between pulses depending on when you trip the shutter button..This is why fluorescent can be a pain to colour correct..Fluorescent lighting often crosses over between magenta and green or somewhere between..