Recently I put a unit of 20 Round Shield Spearmen ( VI campaign ) with level one Armour, into a training queue to upgrade them.
[ I made a slight error, in that the province only had facilities to upgrade to level one Weapons - oops... ]

The unit came out as 100 Round Shield Spearmen with level one Weapons AND level one Armour !
[ I know you can't upgrade a unit type, if that unit type cannot be built in a province ( the game system refuses to let you put it in the queue ) ;
so I am very suprised the game system allowed me to place the Spearmen into the queue here at all !! ]

Anyway, I'll monitor this unit ( in any future battles ) to check it's "makeup" , and advise accordingly.

[ NB : No news yet re those merged units ( Huscarles ) being tracked. ]