Error in bbstyle.css

I am getting this error in the css file generated by bbp-style-pack

Notice: Trying to access array offset on value of type bool in …/wp-content/plugins/bbp-style-pack/css/styles.php on line 2672.

As a workaround, I went into style-pack settings, clicked on the “Latest Activity Widget styling” and chose a custom color for the Latest Activity Widget.

Would be great to fix this in plugin code, so that the workaround is not needed.