I have recently come across several messages related to errors during BW 7.4 update.
I just want to remind people, whenever updating system version to look for the SP note from the next SP from current to the target SP, as this could avoid several issues.
In case of note 11879618, if the correction is not applied before update, it could affect all dependencies on RSCHAVL data elements. If the problem occurs during the update, it is highly recommended to roll back the update and apply notes 1879618 and 1983745 before it.
For further information on this topic, I would also recommend SAP Notes:
1823174 – BW 7.4 changes and customer-specific programs
1978243 – Changes to content 0TCT* due to RSCHAVL conversion