I don't used include/exclude mask when source is on ftp server.
I have done some small test. ftp root contents 1 file and 1 folder, folder with 4 files in it.
I found masks don't work with ftp source as all files are excluded even when any file verifies exclude mask.
May be Luis my knows if there is a way to exclude one folder and it's contents.
If not possible, will be interesting make masks work with ftp sources on Gravity version.