(PSN)Raiver15

That's because you get new items from your foundry. I already explain that in this topic :

Funny enough that bug/hidden option works with warframe too.

Basically, Elite Archimedea loadout will change if the player claim new weapon from his/her foundry (excluding syndicate weapons I believe) so be careful. For example if the player already mastered Dual keres the player can't change Elite loadout with unranked Dual keres prime . However, if the player doesn't master Dual keres but claim Dual keres prime from his/her foundry then that weapon will be add in melee weapons loadout in Elite Archimedea.