Replaced LCD and touch is not working

Hi guys, quick question. I have tried to replace an LCD to a broken Mate 20 Lite and after replacement the touch is not working. Thought that is was a detective replacement and had shipped another one , tried the next replacement and realised that it does the same. Initially I thought that there was a slight chance that I might have damaged the LCD on reassembly but the second one I tried it without putting anything back together and it does the same. Am I missing something? The original broken screen was heavily shattered but the touch was working fine. What am I missing?