Whenever there is a problem on the Payslip, always look at the source of the data, which in this case comes most exclusively from the Payroll Results Cluster Tables.
Since you are saying that in table RT, the amount of WT /560 is 33659.00, then the source of the problem comes either from the configuration of the WTs or from the Payroll Calculation.
Look at all the WTs that are in the Results Table, and try to identify those that are added-up to make Total Gross (WT /101), and then those that are added-up to make Net payments/deductions (WT /110).
Do their totals match the Amount of these WTs?
If not, try to identify which WT in the RT should be into one of these totals (or which one is in the totals and should not be).
Note that you can use t-code PC00_M99_DLGA20 to help you identify which WTs are added-up into /101 or /110.