Purchased content missing for re-download

Hi All I purchased a kids tv show “Spirit riding free” last year for my kids I’ve just gone back to it to check the episodes were downloaded and over half the episodes are now gone I’ve tried to re-download but they arnt available without re-purchasing

a similar thing has happened with a Jurrasic park movie bundle I purchased I went to download one of the films for my daughter using the family sharing as we always do ( kids have their own accounts so they cnt rack up a bill on my account 🤣) and again this film isn’t available to download yet all the others are os this normal when I’ve purchased something we got rid of lots of dvds and purchased the films digitally for us to keep and I thought they’d be accessible regardless of how long ago I bought them if this is the case and they arnt always available I feel like I’ve wasted money

any help would be appreciated

thanks x