I see you originally posted to Duplicate Albums on iPod only
But since the last post on that thread was 6 years ago, you should start your own thread.
Duplicate Albums can be caused by differences in the song tagging.
So if there are track numbers or disc numbers set in one track but not another (or differences) then this can cause album splits. For example if song A has Track 1 of 10 and song B has Track blank of blank, this will cause 2 albums. Replace Track with Disc and you'll see the same problem. Another example is if song A has Track 1 of 10 and song B has Track 2 of 11, this will cause split albums.
Sorting options will also do it. Make sure they are the same.
Also if the Artist has differences.
For example, song A has Artist A and song B has Artist A featuring Artist B, this will cause the splits.
If Compilation has been set differently this will also have that issue. So if song A above has Compilation set off and song B has Compilation set on, this will cause 2 albums to appear.
Artist spelling, capitalization, trailing spaces, leading spaces, punctuation. Same with Album spelling.