I don’t believe it’s a bug, so I’m posting it here.
After a unit is converted, it will always (?) retain the upgrades from it’s original player, and that’s nice, but if the original owner upgrades said type of unit, the converted ones (which are in control of the opponent) will also be upgraded.
There’s an example in this casting, from the YT channel of Grubby:
I believe is nice that the unit retain all he had, but being upgraded, by the original owner, after that, is a little bit too much. I really like the conversion mechanic in AoE 4, but it would be nice if the converted units just didn’t upgrade anymore, in any way, after being converted (just like AoE 2 XD)
And that’s it for now. Thanks for your attention
EDIT: apparently, the example I posted on the video shows how Szalami got the Elite units, and that’s due to new conversions, where the unit was already upgraded. So my bad. You can ignore this post right now XD