I'm in a similar boat as well. It seems like even the built in Appery bits aren't storing it correctly. I have a simple button that stores the text of a page field into a localStorage variable but all I get at the other end is "Label". I wasn't even using Javascript to set that up, I use Appery's built in variable setting (see below)
Is this something that can be fixed on Appery's side or do we have to manually go and recode every single localStorage call?