add comment about potential race condition with signature

packages/contracts-periphery/contracts/universal/op-nft/OptimistInviter.sol

@@ -107,7 +107,13 @@ contract OptimistInviter is Semver, EIP712Upgradeable {
     }
 
     /**
-     * @notice Initializes the OptimistInviter contract, setting the EIP712 context.
+     * @notice Initializes this contract, setting the EIP712 context.
+     *
+     *         When upgrading this contract, make sure to re-initialize and to update the version
+     *         in the EIP712 context to the up-to-date semver by calling __EIP712_init again. After
+     *         the EIP712 version is changed, any signatures that were issued off-chain but not
+     *         claimed yet, will no longer be accepted by the claimInvite function. Please make
+     *         sure to notify the issuers that they must re-issue their invite signatures.
      *
      * @param _name Contract name
      */