offline access + tags in box drive (ios)

Whenever I mark a file (i.e., PDF) offline, there's no problem — I can access them offline.   

BUT

Whenever I mark a folder offline, the offline access feature (which I think should be smart enough to understand that files and folders within a main folder marked offline is inclusive of the subfolders and the files it contain) is not accomplished. 

Here it states that: Files always inherit the status of the folder that contain them.

Said folder contains sub-folders. So I tried marking the subfolders within the main folder offline in hopes that it could remedy their state. As expected, it didn't work. My next option is marking the files, not just the main folder and subfolders, offline. The files within the sub-folders have .boxnote file extension and I noticed that the offline access feature isn't available to such file type — I get a "AN ERROR OCCURRED" message. 

I'm assuming that it's because of the nature of the files being constantly modified, but this is supported in OneNotes for OneDrive, so why Box cannot do the same? Why is this feature unsupported and/or limited to certain condition and files? It's inconvenient. Offline access is very important for most people. Should it be functional in the future, I just hope that changes made will sync correctly, because if not, that's another problem.

On another note, I cannot find the tagging feature in Box Drive as well.