Technically speaking both values are preserved in the history but only one "wins" because each attribute is a last-writer-wins register. This works for most use cases e.g. you wouldn't want two concurrent edits to checkbox to leave it simultaneous true AND false state.

However, when it comes to collaborative text you're absolutely right and support is on our roadmap. A researcher in this space has already implemented his collaborative sequence library on top of Triplit with the Quill text editor and you can check it out here: https://github.com/mweidner037/list-positions-demos/tree/mas...