That sounds like a bug. You could try killing and resurrecting Beast, if he hasn't died at some point yet, to see if that resets whatever the problem is.
Did you use Beast to attack a neutral or friendly NPC (including getting the first hit in on NPCs that would turn hostile after a dialog, etc)? Maybe that reaction got stuck somehow, or there is some kind of alignment issue triggering it.
If you create a new profile (on PC) and start a new game in story difficulty, does this happen if you pick Beast as your avatar and skip through the tutorial until combat, or choose another character, get into Fort Joy and recruit Beast? On console you would have to start the game from a different account, if available, to get a separate drive space for saves (quick or auto saves are per profile, so ones from a new playthrough will overwrite those from an older game).
If you are playing on PC, try verifying local files, to see if that helps, or on console try clearing the cache.
In the Steam library, right click on the game and select Properties, switch to the Local Files tab and then click on the 'Verify Integrity of Game Cache...' button.
With the GOG version, in the (optional) Galaxy client, select Divinity: Original Sin 2 in the left column, then click on the More button, and in the Manage menu select 'Verify / Repair'.
To clear the PS4 cache: press and hold the PlayStation button on the controller, select 'Turn Off PS4', wait another 30 second after it finishes shutting down, and start it again.
On Xbox, to clear the cache:
- press and hold the Xbox button on the front of the console for 10 seconds until it shuts down
- unplug the power cable and wait 30 seconds
- plug the console back in and turn it on
- log into the same Xbox Live account you were using, start the game and let it sync, if required
If that doesn't help and you are playing on PC, please email supportdos2@larian.com with your latest save (or a Dropbox or Google drive link, etc), and possibly the most recent one before recruiting Beast and the oldest after, or the earliest save if he is the avatar character. If you are using any mods, also include a list of those enabled and/or the modsettings.lsx from your profile folder.
Each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin 2 Definitive Edition\PlayerProfiles\<ProfileName>\Savegames\Story' folder.
In Windows Explorer you can zip a file or folder by right clicking on it/them and selecting 'Send To | Compressed (zipped) Folder' (and similarly in OSX/Finder).
PS4 saves can be sent, as well, but they would need to be transferred to a USB flash drive first.
In the Saved Data in System Storage section of the Settings menu, click Copy to USB Storage Device, select the relevant save(s) and Copy. From there you can zip the files, then copy to email or upload somewhere and provide a link.