Local members breaking report when inserting columns

We want to insert several columns between the B and E columns as per the attached. These columns will have local members. When we try to insert a column (new column C) and enter a new local member the header jumps to the left and the local member in column K becomes corrupt. As you can see in columns J, K, M are also corrupt.

We’ve attempted various settings with Attached to Member, Attached to Local member etc but the report still becomes corrupt.

Any ideas what might be wrong?

/Cecilia