Cron Builder: Need to build everytime from scratch

I’m using the cron timer build feature. I realized that I have to build the cron string every time from scratch when I click on the build button. Is this intended to be like this or is this a bug?

I would expect that my previous cron string is entered into the builder.

I think I saw an issue posted on this but could be wrong. I don’t know if it’s intentional or not but it’s worth an issue. It’s not a good behavior.