Recently I faced a strange problem with EncFS. You can find all the details here:
Long story short - according to encfs man page it should handle file names up to "approximately" 189 characters since underlying ext4 FS handles up to 255 characters (formula: 3*(N-2)/4). But in practice I couldn't create a file with name containing 145 characters. Syncthing developers and I couldn't figure out why.
I believe it's because by file name you mean absolute file name, but I'm not sure about it and it's not clear from the documentation. Perhaps you could give more details on what are limits on maximum file name length and absolute file name length.
The limit is 176 characters and I will fix up the man page.
Is it because filenames are encoded in Base64? It would help if the man page stated that.