Each field carries this device's position number for the last envelope that wrote it; an incoming edit applies only if later in chain order; different fields both survive, the same field picks one winner silently.

It is the exact merge rule, and the design rule that follows.

Every field in a row carries a sticker. The sticker is this device's position number for the last envelope that wrote the field. Two devices write different numbers, but agree on the order.

An incoming edit is a comparison. Later in the chain than the sticker? Write it, and replace the sticker. Earlier? Drop it.

Later means later in chain order. Not later by the clock. Two clocks are never compared.

Alice sets the title. Bob sets the tags. Both offline. Different fields. Different stickers. Both survive, on both devices.

Both set the title. Chain order picks one. The other is gone, everywhere, and nobody is told.

Fields that people edit at the same time should be different fields. Write the one path you changed. Never the whole record.

Check yourself. Alice sets the title and Bob sets the tags, both offline. What do both devices end with?