Incorrect material number was transferred

What causes this issue?

In parameter INOUT_NEXT_MATNR, material number &V1& was transferred as
the starting point. This material number, however, is not contained in
table INOUT_MATNR_TAB. Normally, this inconsistency should not occur if
the values are transferred to INOUT_NEXT_MATNR and INOUT_MATNR_TAB in
subsequent calls as they were returned in previous calls of the
function module.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Find out how an incorrect material number was saved in parameter
INOUT_NEXT_MATNR. During the first call, the function module was
possibly called without using the initial parameter INOUT_NEXT_MATNR
within a sequence of blocked calls.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.