Hey everyone, there was a bug in the previous build of the game that may have impacted the way that save files were migrated from the base game to the DLC.
Essentially when running the game for the first time after installing the DLC, the game is supposed to migrate your save file forward from the old format to the new one which the DLC runs on. This is a one time trigger that happens the first time you run the game. Because the game uses Steam Cloud to keep all your devices in sync, this had a negative side effect of the game considering the Steam Cloud save as the current data.
This would result in your save appearing to be erased, with a brand new set of data when loading up the game.
Good news: If you haven't run the game yet, or are a new player reading this, the bug has been fixed and this issue won't affect you at all.
For everyone else...
Option Added to Re-Migrate
The game has been updated with a new option to migrate your data from the base game to the DLC manually. You can find it in the Extras menu from the title screen. If you click "Migrate Data" you'll get a warning pop up (since this will replace the DLC progress with your full progress from the base game).
Clicking this will restore all previous progress you had before the DLC, but will replace any new progress you've made on the DLC.
Apologies for the bug introduced in the previous version, hopefully not too many players were affected. As always, let me know if you run into any more issues!