Bug Info: Hide and Seek may inadvertently reset to player level to level 1 upon completion of game mode, however fixes itself when re-entering freeroam.
Platform: Windows PC, Series S/X (may apply to all platforms)
Edition: Premium with all Car Packs as of this writing (should apply to Standard Edition)
Content Update: Hide & Seek was added to this update.
Edit 1: I can confirm that this happened to me.