I hope it's OK to label this behaviour as a bug, but I think it's justified.
The behaviour for opening a folder or file within CryptDrive is not what would be expected on a mobile phone browser. The normal expectation on a phone browser is that a single-press will open links, with a long-press to open a context menu. However, on CryptDrive (at least on Firefox mobile) a single-press selects a folder or file; in order to open in you need to either double-tap it or long-press and select "open" from the context menu.
I'm afraid this is probably a show-stopper in using CryptDrive as a drop-in replacement for Google Drive as it will cause aggravation for non-tech-savvy users.
Single-pressing a folder or file within CryptDrive on a mobile browser should open the folder or file.
