I have been receiving this error again and again. But I couldn’t edit the formula. There are somewhat updates in the system which prevents me from locating this formula.
It’s a template doc so you should be able to find it in the workflow or report tab. Have you checked that [Related Orders by Customer Name] is actually a list? Is [OrderID] the key column name in the parent table?
It is not like before. I can find its workflow and report tab but it doesn’t contain the formula anymore.
The problem is in the template the workflow rule uses. Look in the template file.