Using UPDATE with a recursive query - not working (error #1241)

I have a recursive query that works perfectly. Here it is:

WITH RECURSIVE mgmt_levels AS ( SELECT jobholder_uid, positionmgr_uid, position_level FROM positions WHERE positionmgr_uid = 'foo.bar@company.com'
UNION ALL
SELECT p.jobholder_uid, p.positionmgr_uid, p.position_level FROM positions p INNER JOIN mgmt_levels ml ON ml.jobholder_uid = p.positionmgr_uid )
SELECT jobholder_uid, positionmgr_uid, position_level
FROM mgmt_levels ml;

However, if I now want to perform an 'UPDATE' to the output from the original (successful) query, I get an error (#1241 - Operand should contain 1 column(s)). I looked up this error but I don't see where I have made the error. What am I missing here? Thank you! Here is my UPDATE code ...

UPDATE positions SET bu_div = 'Customer Services' WHERE jobholder_uid IN
(
WITH RECURSIVE mgmt_levels AS ( SELECT jobholder_uid, positionmgr_uid, position_level, bu_div FROM positions WHERE positionmgr_uid = 'foo.bar@company.com'
UNION ALL
SELECT p.jobholder_uid, p.positionmgr_uid, p.position_level, p.bu_div FROM positions p INNER JOIN mgmt_levels ml ON ml.jobholder_uid = p.positionmgr_uid )
SELECT jobholder_uid, positionmgr_uid, position_level, bu_div
FROM mgmt_levels ml
);