Bookmarks disappear after closing browser app on iOS 

Hi there, 

aftter a bit of work i managed to use epub reader in a nuxt app. 
Now i'm having this silly issue. Everytime i close my browser window on mobile the bookmarks disappear. 
It is a bit weird since the poisition and all other data are stored correctly. 

Any helpful infos or solutions? 

thank you 
Nando   