Special char in CPQ Text Fields

Problem Statement: CPQ BML error is displayed when Sales users add special char (|) in CPQ text fields and Saves the quote

What are the special characters allowed in CPQ text fields?

What are accepted/ rejected char?

Use cases: When user enters TEST||| TEST in a text area field and Saves the quote, system throws a large BML error

When user enters TEST~~~~~~TEST in a text area field and Saves the quote, system Saving only TEST. All characters starting with ~ are not Saved