I hope this will be fixed soon as possible. Ht are useless know. Legendary engine artifact and others for ht as well. Splash damage researches in library doesnt work in that way.
Ok, when I was playing on monday, splash damage was not working for sure, but when I tried yesterday after posting here, it was once again working... Yet, my HT still seem less powerful, like the HP and damage bonus from Leonardo do not apply.