Post the G-code so can have a look.

Like as been said earlier seems Linux CNC as a quirk and if the P or Q parameter isn't stated then G64 will be ignored so if Cambam is just putting out G64 then chances are your not actually in G64.?

Try this copy the G-code file then Delete any reference to G64 or G61 from the G-code file. Next in MDI type G64 P0 Q0 then run the code again.
G64 will stay inaffect because it's Modal and will now be used for the complete program and the rest of the session unless changed by G61 or G61.1