Painting - What kind of paint is this?

I am painting a new unprimed 30x80 hollow core interior door. First I primed it using a good quality primer. I didn't have enough white paint at home to complete the job, so I went to the local hardware store to get more. They no longer carry what I usually used for interior wood trim (Titanium paint by paintcafe.com) so I picked up a quart of Pittsburg Performance Plus, latex, deep base, eggshell paint. Well it's terrible paint! It's more like glue than paint, won't hide the brush marks from the primer, very little if any coverage. And it doesn't even clean up with water like a normal latex paint. Kind of gooey and stringy.
Q. Is there any possibility that something was supposed to be mixed with this paint before it was used, or do you think it may have once been frozen? Thanks.

Well few things, deep base paints never are great in the coverage department, why did you need deep base for a white finish, primer should be tinted to close to the finish color if indeed you went deep with the color, Why you jumped from white primer to deep base paint to finish the job is an unknown, and yes it sounds like the paint has gone bad.....I would return it to the store and see what they say...

Thanks BB, I will return it tomorrow and see what they say. Actually, I didn't even notice the can said "deep base"; I was in a hurry and the service was lousy. So when the girl said the Pittsburg paint was what she recommended. I just grabbed the Eggshell finish and headed to the cash. Just looked at the can again, it doesn't even say "White", but I guess all paint is "white" until you tint it?

What you bought was a tint base.This is a lightly pigmented base that needs tint,including white tint,to be complete.With deep base you bought the least prepigmented base of them all because it's designed for deep shades.

Take it back and buy a can that actually says white on it.

All tint bases are designed to be used with tint added never untinted and no...not all paint or all bases are white.They will need white added just like any other tints to make the shade desired.

I'm not trying to be mean but next time wait until some help is available.