Up until now, they have worked fine. I make sure to indicate the disk number (1/2, 2/2, etc), I scan them in, and they show up in Please under a single album as Disk 1 and Disk 2 (etc)
NOW… thew show up as separate albums of the same name, with each album having its own set of tracks.
I went to an existing album that was good (disk 1 and disk 2 in one album) and did the plex dance, and now it it tow albums.
This appears to be a known issue in the web app. It is already fixed in the alpha version which I have available here. So it won’t be long until it lands in the public web app.