I can’t replicate it again, but it kept happening in one game.
In stage 2, start with one dev. Start a game engine. Click to train the dev. It will start training and instantly finish the engine.
When I had 3 employees I’d get the other 2 to start training. Then start engine with my only remaining employee (myself). Then train him/her. That also worked.
I’ll try to pay attention and replicate. My memory is fuzzy, it was pretty late 
I got it!
Does NOT work:
Start engine, send everyone training.
What works:
Have a tired person.
Start engine. Train everyone except tired people. Send tired person on vacation.
Once you do that the engine is immediately finished.
interesting. thanks for reporting this!
I’m going to regret reporting this.
Now how am I going to maximize my next playthrough’s performance? I did 14 game engines last time. Assuming they take a month each to complete, that saves 14 months, or roughly 4% of the total gameplay time!
I’m gonna manually add 4% to my score now. There!
Also;
Have every staff member tired
Start working on engine (Or do this first, I don’t think it matters.)
Send your tired staff on vacation
Train the CEO
PS: Sorry for bumping a fairly old post.