weird behaviour when connecting iPhone to itunes messing up my music library on iPhone 6

Hi dear community,
So i have got this on going for some time and haven't been able to find a solution for it. Sometimes on rare occasions when i connect my iphone to the pc, it messes up my music libraby and sometimes splits up albums into to of the same album witch is really confusing. and today, it made it do again but added the same album and made the first 30 or so numbers unrecognisable and replace the titles of the songs with numbers, the artists are still correct though. it was an album witch i purchased and all albums were purchased and being messed with. How to reproduce this and get it back to the old?