Limit cart Value limit is disabled when no value amount is set

Dear experts,

While creating a limit SC if user enters no amount on the popup and clicks on 'OK', 'Value Limit' field turned greyed out at item level, but where as if user chooses some value (ex 10) and click on 'OK' we've no issues. the 'Value Limit' field turned on. Kindly guide is that standard behaviour?

Thank you

Arun.K.P