Seems this issue just started. I open my Music library and select an artist. When I then select an album, the first song in the album will play automatically. IIRC, I used to simply click within the album icon, but not on the play button, and the album would open, allowing me to select individual tracks. This does not happen anymore. Is it just me?
Are you in Grid view or Summary/Detail view? In Grid view, it works per your recollection. In Detail view, clicking the album cover will play. If you just want to open the album, click somewhere else on the line.