Minseok Joo writes: ” First, I would like to apologize for everyone who had inconvenience since Season 1 Update. Everyones support is incredibly appreciated, and our Dev Team is currently doing our greatest effort to resolve the current issue. Throughout this Dev Note, we would like to share some countermeasures regarding the Invasion Dungeon and Haileys farming difficulty issue.”
Source: N4G PC The First Descendant – Dev Note vol.13