Greetings, Tenno!
Today we have updates about a bug that was reported this week in Warframe. Some players previously purchased a Riven Cipher from Teshin and an Archon Shard from Chipper in the same week. Even after the weekly reset occurs, they reported they can’t purchase these items anymore. This was an internal bug related to how we handle timed purchases from NPCs, and should not have any impact on the in-game market or storefront purchases.
As of the posting of this thread, we have patched the servers live so that the bug stops happening and no additional players will be affected. Additionally, (after a relog) any affected players who couldn’t make their timed purchases from Teshin/Chipper should now be able to.
If you continue to have any issues with these timed purchases from NPC vendors, please respond immediately so we can correct any lingering cases. Thanks for your patience and understanding.