Subtitle-Tool / CPS not working?

Hi, I'm so glad subtitling was finally implemented! However there is an issue with the CPS-display: it merely shows the number of characters in a title, but not PER SECOND.

I wanted to work on a feature film with DaVinci but this bug makes it virtually unusable for the job - I simply have no clue what I'm doing. Is this a known issue? Am I overlooking something?

I'm running 15.1.1.005 on a Windows machine.

Thanks for your help!