Funky Yeast Smell From Vial

I made a starter last night using White Labs Cal ale yeast. When I cracked the vial open, it fizzed quite a bit (which isn't too uncommon for white labs vials) but it had a hint of an odor that reminded me of a sour beer.

I went ahead with the starter to see what it would smell like when it was done. After ~ 12 hrs it looks normal and doesn't smell abnormal but I am a little skeptical of this vial having some sort of bacterial contamination.

The exp date is May 20 but I have had it in my fridge for about 2 months. I once had a vial that smelled of sulfur and that made a terrible beer but I didn't make a starter with it so I am on the fence whether to chance it or delay brewing to get a new vial.

Any thoughts / experience with this?

Yeast smells. Sometimes in a vial sour, because it's putting off co2 while in the tube (that's why it fizzes.) Relax.

Fermentation is usually ugly and stinky.....