The FT-817 is probably the most tested for the DRAWS™ HAT.

Are you using the left DIN-6 port and selecting the same in your program?

There is a possibility that one of the flags in the CODEC was set incorrectly, at some point.  Try using n7nix/bin/setalsa-ft817.sh  

Occasionally, we have seen the FT-817 where a parameter is changed from default, sometimes doing a full reset on the radio gets it to a working mode.