Something is wrong with the SY09400 table.. it's missing a lot of entries for the POP module (and possibly others) after I upgraded a site from GP 2015 (14.0.1230) thru 18.4.1361 to 18.5.1661.. 
Customer is complaining about missing menu entries under purchasing transactions..  Select Payables Cheque is one of them.. 
Comparing SY09400 in 2015 has 211 rows related to Purchasing Windows, but there are only 18 rows after the upgrade left..