Same thing happened to me - and others (separate post here).
Note that you can boot and test the otherwise assembled laptop even without the input cover. You can connect and external keyboard and mouse through USB and then boot using the tiny power button directly on the mainboard. You might have to disconnect the charger and unplug and replug the battery first.
I have my framework completely set up this way. Now I am waiting for a response from support about a replacement input cover