At times it can become possible that your PC Steam or PC Epic Games Store save data is corrupted which can cause other issues. As an attempted fix you can try these following steps to clear / delete / remove it to ensure a fresh state:
1) In Steam > Settings > Cloud, disable Steam cloud sync. We don't want Steam to restore the files we're about to delete
2) Exit Steam completely
3) Go to the following location: C:\Program Files (x86)\Steam\userdata
4) You should see a folder with a name made up of lots of numbers. That's your Steam ID, and holds all the save data associated with your Steam account. Go into that folder.
5) Find the folder named with your game code below(such as 448080 for Fibbage XL). That's the App ID for your game. Go into that folder, then go into the "remote" folder.
6) When you See the UserData.sav folder (It will be followed by a bunch of numbers), delete it.
Once you're done with everything, you can open Steam back up
uninstall and reinstall the packs, and try opening them again. If everything works, you can re-enable Steam Cloud Sync.
Also note that there may be an additional location in that folder (with your user name) which may contain data if nothing is clearing to try: C:\Users\YourUserName\AppData\Local\Jackbox Games\
Steam AppID List for Jackbox Games Products:
Fibbage XL: 448080
Drawful 2: 442070
The Jackbox Party Pack: 331670
The Jackbox Party Pack 2 : 397460
The Jackbox Party Pack 3: 331670
The Jackbox Party Pack 4: 610180
The Jackbox Party Pack 5: 774461
The Jackbox Party Pack 6: 1005300