Congratulations for becoming an official dev. TriRem! 
(I guess that’s also why you edited your original post several days after the thread had gone silent).
Now that’s the case I wanted to report to you the same mistake as concerning the unofficial aoe2techtree.net, the ingame tech tree wrongly gives for the castle age serjeant its feudal age stats.
Especially for casual players analyzing the tech tree before choosing the civ. they want to pick, this might be a problem, as they will underestimate the unit they will be able to train and may not even want to train it in the first place, let alone know about the significant buff their serjeants get as soon as Castle Age is hit.