Riftbound runes are counted as units and misplaced into main deck

Problem

A Featurebase report says Riftbound Rune cards are being treated like Unit/main-deck cards in the deckbuilder. The reporter says the Unit card copy lock is applied to Runes, preventing more than three copies, and that Runes are added into the main deck first instead of the Rune section. That makes otherwise legal decks fail save/upload for events.

Source / Evidence

Featurebase post: https://cardeio.featurebase.app/p/bug-important-runes
Submission ID: 6a240d810b4552cff10d6944
Reporter: Miguel Angel B (wolfinstown@hotmail.com)
Date: 2026-06-06 12:07 UTC
Upvotes: 1
Screenshot attached on Featurebase.

Reporter text:

There's a bug in the rune list; the card unit "lock" also applies to runes and doesn't allow more than three runes. Therefore, it prevents decks from being uploaded to events or saved because they're illegal. Can you fix this? Thanks.

P.S.: It also puts them in the main deck, and then you have to drag them down to the runes section.

Duplicate Review

No exact active Linear duplicate found for Rune-specific section placement/copy-limit behavior. Related but not exact:

HYD2-7219 covers prohibiting token cards in all Riftbound deck sections.
SENG-282 covers Riftbound special-zone display/import fragility for Legend/Champion/Battlefield.
HYD2-7345 covers broader deck editor card-count mismatch before event submission.

This ticket should stay narrowly scoped to Rune cards being classified/placed/validated incorrectly.

Expected Outcome

Adding or importing a Rune card places it in the Rune Pool / Runes section by default, not the main deck.
Rune cards are not constrained by Unit/main-deck copy-limit behavior.
Legal Riftbound decks with valid Runes can be saved and submitted to events.
Invalid Rune placement still produces clear validation copy.
Regression coverage exists for manual add, text/import, save, and event-upload paths.