If an account is set up as a Rep Payee account, does anyone allow the beneficiary to cash checks off of this account?
Our situation is that the Rep Payee usually issues Bill Pay checks to the beneficiary, and then the beneficiary comes and cashes though.

Yes, if the beneficiary is payee on the check, we would cash it.

Absolutely. This is typically how the beneficiary gets their "allowance"/spending money from the rep payee. Especially common if the rep is a business.

We would based on the same comments above.

When you first described it as "cashing checks off the account," I was concerned you were referring to checks payable to the beneficiary by third parties, and the beneficiary cashing them based on some confused idea that if one of them bounced, you could charge it back to the Rep Payee account. THAT would be a non-starter, since you would not have the right to recover against the account.