ASSERT condition in class &1, method &2, row &3 has been violated

What causes this issue?

An ASSERT condition has been violated. Instead of the ASSERT the system
triggered an exception with the category /PM0/CX_ABX_ASSERT.

System Response

The exception was caught and any incorrect processes were reversed. The
corresponding objects have been excluded from further processing.
Alternatively, the exception was not caught; this leads to a short dump
in an ASSERT. Any changes that have not already been persisted were
reversed.

How to fix this error?

The trigger condition for the ASSERT or exception must be prevented.
This is a serious error and must be avoided.
Inform your development department, consultant, or SAP.
Check whether the application log contains an error message before the
ASSERT.
Check the objects (policy, contract) that were processed when the
exception was triggered.
The corresponding ASSERT is inactive and can be activated using the
checkpoint group /PM0/ABX_ASSERT (this immediately terminates pr
ocessing).
Alternatively, log points can also be activated using this checkpoint
group or the logging of the ASSERT can be activated.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.