Situation: Player has market lvl 11 being built right now, there is market 12 queued afterwards. If he was to abort the lvl 11 that is currently being built there is a popup "cancelling will return xyz ressources, are you sure?"
If lvl 11 is being cancelled it also removes the market lvl 12 that was in the building queue, ressources from that building are NOT mentioned in the popup and may potentially get lost if going over warehouse limits.
Works with any building and not just market