Something I’m wondering about

I noticed that some manga/doujin aren’t listed as part of Fakku unlimited nor do they have a price listed. An example of this is ‘Sex Island’ by the Circle ‘Pine’.

Some titles were offered for individual sale but the publishing rights were dropped later. It appears that Sex Island was one of those. Looks like I purchased that title back in 2018. Evidently, once purchased, the title can still be downloaded after the rights are dropped as I was able to re-download it just now.

Thanks for the explanation.