I just restarted the campaign recently. After I talk to the ruler of Gilden and get sent to find the evidence about the threat from the east, I'm supposed to get a Pioneer unit while moving away from the city.

The event fires but I don't get a pioneer. I have 2 ideas on what might be causing this:

1) When I restarted the campaign, unlike the first time, I had like 4 different sets of starting units (Peasants, Peons and Pioneers) which differed only in appearance. I retired 3 sets in order to keep only one. The game might be failing to spawn in retired Pioneer design.

2) I trained a Pioneer in my initial town and sent it to found another one close to the Earth Shard near New Pariden.

Any ideas on how to fix this? Is it possible to unretire a design?