"Could not find foo in PATH" - but it's right there

I see the following behavior:

$ foo
Could not find foo in PATH
$ which foo
/usr/local/corp/bin/foo
$ readlink -f which foo
/path/to/opt/foo/foo
$ /usr/local/corp/bin/foo
starting foo, output for foo, blah blah blah

this is a Centos 7 machine with Linux kernel 3.10.0-1160.53.1.el7.x86_64 . The shell is bash. Notes: * Yes, /usr/local/corp/bin is in my $PATH. * /usr/local/corp/bin/foo is a symlink to /path/to/actual/binary/foo. * hash -r doesn't help.