You can only complete 2 frames each week. Once you do, they're the only ones available for purchase.
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the thing is, i only have the machinegun and the sniper frame available and on my other characters i have all,
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Have you completed two powerful frames on your other characters this week? Ada will show all frames available until you’ve completed two powerful ones during the week. Then until the weekly reset those two frames will be the only two you can see.