Don't see any other discussion going back a few months bringing this up, so I'm going out on a limb and looking to see if anyone is having the same issues I am having with Nat Spain getting crushed in a matter of weeks by the Reds. No joke. I'm used to the engagement going on for at least a couple months and so take my time before I send volunteers (mainly so I can send more than just 2). The first time I tried this, it seemed to end mysteriously quickly. I remember getting the popup for sending help, and forgetting about it for about a week. Then it seemed like no time passed at all and the damn civil war was already over! But that's not the worst part... Both times it was the Reds that came out on top, which means a stability hit (-2%) and a drop in popularity (another -2%).
Because I didn't want the same thing to happen the first time and just ignore it, I tried to swoop in to save the day right when the fighting started. I sent them a little fuel and 2 divisions of my best crack troops with Schorner leading them. I watched the battles progress with no information before my troops got there, and it seemed like the Reds were pummeling the Fash from the word GO. They lost Sevilla in 2 weeks... Week 3, when Schorner finally showed up, it was a complete rout by that point. Italy's troops got there at the same time as mine did and I chuckled a bit when I saw they were content to just sit on the coastline and wait for the inevitable.
Needless to say, none of the volunteers saw combat because the civil war was over a couple days later.
I didn't get much info in the weeks leading up to the complete Red steamroll, but when I counted what was there it came out with Falangists=11 Divisions Reds=24 Divisions.
So either the Reds completely surrounded and captured at least 10 Fascist divisions in 2 weeks or the Reds started the civil war with a marked advantage in firepower and manpower. The Soviets didn't even need to show up it was so bad...