Plexamp seems only to be displaying a partial list of EP’s (don’t know about albums but presume same behavior) on artists with a lot of them. I have to click into the “Singles and EP’s” section to see the full list, kind of misleading making me think I had lost some of them.
This is seem on both the MacOS and iOS versions, can’t test anything else.
Potentially add a toggle in the Appearance settings to display the full list?