We have these in-line next to actual p-buttons. Those buttons are using p-button-text to remove the background color.SplitButton uses button and menu components internally, refer to their documentation for the detailed style list.
These classes do not work with the splitbutton. The only ones that work are things like p-button-primary and p-button-secondary.
Do the devs read these forums? Should I open a GitHub issue for things like this?