The error about OpenType Layout Feature (OTLF). The syntax should be recheck on OT mode active. "}" is standard syntax for moreover feature. Here we need more right syntax and we must care when draw them. For instance:
feature smcp { # Small capitals
# Latin
sub @lc by @sc; -------> here always closing by ";" and @lc/@sc were indicating classes
} smcp;
Just a few bit wrong code, we will get error shower

But overall, think OTLF will be recognize as well when generating OT. You can write the specific script on the OpenType feature for good solving. Sure here more expert for your good sense

. Thanks.
Best regards