Okay, so ive been playing BI, as the Moors, and having settled into an alliance with the WRE, ive been taking on former allies the WRE Rebels. Their only settlement in Africa is Lepcis Magna, which had a mediocre garrison, which i besieged with a moderate force (more than enough to take out what they had to offer), and they had a small relief force coming from the east, 2 peasents and a family member. My spy had seen the relief force prior to them reaching Lepcis, and my assassin was successfully able to kill the family member.
Next turn however, the relief force had reached Lepcis, as i had planned (bringing the battle onto an open field), but they had another general!! They couldnt have gotten another family member from anywhere else, as it was the middle of the desert and my spy and assassin wouldve seen him appear, so it seems he simply appeared out of thin air!!

How could this happen??

There werent even any WRE forces nearby to turn and join the Rebels, and there were no other forces in the vicinity that coulda been bribed! So where did they come from?!