Does Bellows Breath repeated create two triggers on the stack?

No, Bellows Breath with Repeat does not create two separate triggered abilities, nor does it place two items on the chain.

According to Rule 820.1.d, Repeat is a keyword that allows you to pay an additional cost to execute the instructions of the spell a second time. It does not create a new spell or a new item on the chain. Instead, it modifies the existing spell to perform its effect twice upon resolution.

Here is the breakdown of how this works:

1. Playing the Spell: When you play Bellows Breath and pay the Repeat cost, the spell remains a single item on the chain (Rule 820.3.a).
2. Resolution: When the spell resolves, it executes its effect ("Deal 1 to up to three units at the same location") once, and then immediately executes that same effect a second time.
3. One Continuous Event: Because this occurs during the resolution of a single spell, there is no opportunity for players to react or play actions between the first and second instance of damage (Rule 820.1.d.1).
4. No Triggered Abilities: The repeated execution of the spell's effect is not a "triggered ability" that gets added to the chain; it is simply the spell resolving its instructions twice.

For more information on the interactions of this spell, refer to RiftJudge FAQ #8810, which explains that while the instances of damage are separate, they are both part of the same spell resolution process.