I am experiencing a critical script error in the "Visite guidée de l'économie" (Learning the Ropes - Economy) mission in the latest Alpha 28 (Bolorix) version. I tried in english and in french and got the same error

I meant if the name is the same i'm not sure what happens. Like if you did <BonusCavMelee> on template_unit, but then also on did <BonusCavMelee> on template_unit_infantry. Probably the template_unit_infantry will just "win"- as in those values will be used for that specific bonus- but yeah you need to test. Other than that i don't think theres a limit you need to worry about when applying different bonuses to the same unit.

oh baby strong they are... but they are super gimmicky, they require too much economic focus on them (rigidity of economy) and they are slow as hell... as one of the few players who uses eles widely in multiplayer, I would say it is underrated... and it shall remain so, for quite good reasons. again: DO. NOT. TOUCH. MY. ELEPHANTS. <3

So far the only way to get someone to join has been by changing the mod.json;  "ignoreInCompatibilityChecks": true, but now anyone will be able to join and it will throw a lot of peopel off

Oh, you mean duplications as in using multiple bonuses for the same unit? Will have to test if e.g. giving a units a 100x multiplier against buildings but a 0.01x multiplier against heroes breaks anything.