When a spool's two chips read as two spools

You tagged a spool with a chip on each face, and your inventory now shows two entries instead of one. Each chip works; each opens its own spool. The weight you correct on one never appears on the other.

Nothing is broken. The two chips were almost certainly never a pair.

The test that settles it

Two chips are a pair because they carry the same Twin Tag ID — a value written at the moment of writing, shared only by chips written in the same session. Read both chips and compare that value: it is the whole diagnosis. Tiger Studio shows it; so does any reader that decodes the payload.

The full rule, including what else has to match and why the timestamp alone is not proof, is on the TigerTag chip.

Different values: they were never a pair

This is the ordinary cause, and it has one origin: the two chips were written in two separate passes. A second pass happens a second later or a day later, so it stamps a different Twin Tag ID, and nothing binds the two chips from that moment on. Every tool downstream is right to count two spools.

There is no repair short of rewriting. A pair is made at write time or not at all.

Rewriting them as one pair

Erase both chips, then write them together in a single session:

	How the pair is written	Best for
Phone — Tiger NFC Connect	Dual NFC: one form, then chip 1/2 and 2/2 in the same session	one spool, no hardware
Desktop, two readers — TigerPOD	both chips at once, in one pass	a shelf, a batch
Desktop, one reader	not possible in one pass — this is how the problem was created	—

The phone procedure, including the rule that the chip you scanned first is the one the app expects as 1/2, is in your first smart spool.

The single-reader case is the reason the TigerPOD holds two readers facing each other: one pass, one timestamp, one pair.

Same value, still two entries

Rarer, and worth reporting. The Twin Tag ID is necessary but not sufficient — the two chips must also describe the same spool, field for field: brand, material, the three colours, both aspects. Compare those next.

If every field matches and your inventory still splits the spool in two, that is a bug rather than a mis-write. Say so on the Discord with both chip readouts.