complete=enhance and bindkey \t complete-word-fwd interact badly with word delimiters

[pistole]

labrys:~/t> echo $version
tcsh 6.22.03 (Astron) 2020-11-18 (x86_64-unknown-linux) options wide,nls,dl,al,kan,sm,rh,color,filec
labrys:~/t> set complete=enhance
labrys:~/t> bindkey '\t' complete-word-fwd
labrys:~/t> touch asdf_conf
labrys:~/t> touch _config

Typing ls _con and hitting tab completes to asdf_conf. Hitting tab again should cycle to _config, but instead drops the completion to asdf_ and beeps.

This also happens with at least - and . (eg, asdf.conf and .config)