When I enter Song Setup | Meta Information and add data for the first time it works ok. However, when I want to edit the informtion (for example to correct a typo) that does not get saved. Also, the Apply-button does not get un-greyed at this time.
I found a workaround for now: check the "Pop-up when song opens" checkbox, that makes the Apply-button to be ungreyed, and uncheck the checkbox again if desired. Now the edits I made get save once hitting the Apply button.
Studio One 4.6.1.55987
Windows 10 Pro 10.0.18363