Warning: Differing charts of accounts (& - &).

What causes this issue?

You want to display or change cost element/account groups. However, cost
element group &V3& is assigned to chart of accounts &V1&, whereas the
given controlling area &V4& uses chart of accounts &V2&.

How to fix this error?

Change the controlling area to one using chart of accounts &V1&.
In active master data validation, the cost elements/accounts are always
checked against the controlling area. If you use a different chart of
accounts, the validation will issue incorrect results.
Also note that you may change cost element/account groups without
meaning to do so, if these groups are assigned via the differing chart
of accounts to other controlling areas. In spite of this, the system
allows changes for two reasons:
The chart of accounts no longer exists and is not assigned to any
controlling area. You can delete the cost elements/accounts used there.
You purposely change the cost element/account groups in the chart of
accounts and do not want to set another controlling area.

Error message extract from SAP system. Copyright SAP SE.