I'm designing a handwriten font wich contain many alternate sets of characters and I programmed a calt feature to randomize it. The feature contains a lot of lines mixing and conditioning the substition of each character. I thing the sintaxis is fine and the replacement works fine too, but when I increase the number of characters in each of the classes used in the code the output panel shows the following warning:
[FATAL] GSUB feature 'ÿÿÿÿ' causes overflow of offset to a subtable (0x1140a)
(I don't know why the name of the feature is swhown without the correct name).