Despite the large quantity of maps, it's possible to come across the same map after exiting a dungeon. In this case, the portal will open to a partially- or fully-cleared map. Introducing intentional clones for the same dungeons and tiers will reduce the likelihood of that happening even further, at the expense of at least doubling the generated boilerplate files.
While collisions are already rare, going for 3x or even 10x the amount of clones even might be ideal to realistically purge the odds of finding an exact duplicate.
Using modifiers like "volatile" seem to work to a certain extent - they are maybe time-based though so the level won't clean-up in the timespan where you would find the same map on the same tier again (likely immediately after leaving the previous instance). This hasn't been properly verified but clone would solve this issue anyways.
Despite the large quantity of maps, it's possible to come across the same map after exiting a dungeon. In this case, the portal will open to a partially- or fully-cleared map. Introducing intentional clones for the same dungeons and tiers will reduce the likelihood of that happening even further, at the expense of at least doubling the generated boilerplate files.
While collisions are already rare, going for 3x or even 10x the amount of clones even might be ideal to realistically purge the odds of finding an exact duplicate.
Using modifiers like "volatile" seem to work to a certain extent - they are maybe time-based though so the level won't clean-up in the timespan where you would find the same map on the same tier again (likely immediately after leaving the previous instance). This hasn't been properly verified but clone would solve this issue anyways.