In order for shield research to appear you must be on the default player force. The other forces are missing out on this advantage.

The research doesn't show on the default force when loading older maps either, but research availability for all forces may help remedy that issue too.

fixed :)
in normal games, it should have worked before.
you can disable and re-enable research, then it should show up 100%.
or use the command "ts refresh" (does basically the same)
i don't know what caused that issue but it should have been fixed in version 19 already