This is my first time posting here and in all honesty, a little nervous. Please excuse me if I don’t use the correct terminology. Moving on…
Here’s the thought;
Introduce a final stage that’s called ‘Explore’. This is like a proposal stage only it has a zero day time period. At any point during the voting process a new proposal can be injected there. If quorum for the existing proposal is reached during the ‘Promotion’ phase then we pass through the ‘Explore’ phase and any additional proposal is ignored. If quorum is not reached during the ‘Promotion’ phase then the additional proposal is cycled into the ‘Exploration’ phase.
If multiple proposals enter ‘Explore’ during the voting period, then a time period is introduced, and as a result, a 5th voting period. Stakeholders vote on which proposal they want to enter the ‘Exploration’ phase like they do any ‘Proposal’ period.