For some reason, in the change speed duration option, I am getting number of frames instead of seconds. How do I show seconds in this panel? I'm using cc 2019 on Windows 10 - 64 bit.
What is your sequence timecode display set to?
Your timeline is set to audio units
Also your time display is non standard 30.04 fps.
Guessing your are using footage that is variable frame rate.
So what should I do?
Right click on the number display and choose the format you want to see from the drop down menu:
My guess is like what Ann said, that your timecode is set to a non standard 30.04 fps. Do you have those timecode options available if you create a sequence with 29.97 fps? Testing that out in another sequence with a standard frame rate might answer things. You could even copy and paste your footage into the new sequence and compare.