This seems like a Reset Dungeon issue, or is it supposed to be like this?
From FAQ on Discord (@EHG_Kain)
We would optimally like to have map permanence, however this is normal for our maps as it reduces load to help with performance.
Because we don’t encourage vendor runs (items sell for very little), and all endgame activities are failed if you leave them before completing them, going to town and returning to a map is generally a rare activity in Last Epoch. This in addition to the performance benefits has resulted in map permanence being lower priority.
We understand this in particular tends to affect new players, as it’s a habit of regularly returning to town to sell items from other games - even if this is not an encouraged activity in Last Epoch. As such we would like to add map permanence in the future.