As you add parts to soldiers, such as armor, the time it takes to build increases. Also, if you train groups or such, it actually triples the time, sometimes even greater time.

No, you guys misunderstand what I'm saying. I'm talking about vanilla units like pioneers suddenly taking 8 seasons to produce instead of just four.

When I asked about conditions I was asking if there was some hidden stat causing this, like maybe if you have a high pop production takes longer or something along those lines.