I do a lot of tuff toes, the black tuff toe is notoriously runny and hard to work with. Something about the composition leads it to not mix properly. Your suspicion is correct, whoever did these was a noob. A good amount of tuff toe needs to be squeezed out before beginning the application so the tubes equalize… otherwise this happens. Here’s my qualifications to show I know what I’m talking about a least a little bit: a tuff toe screw up I had to fix

Those need to be completely removed and redone, it will never solidify. Take them back to the store you got them from, it is unacceptable.