TEMP SOLUTION:
Same happened to me. This is defininetly a software issue and came up when updated the IOS, but I think I found a work around until they fix it.
So every time I’m connecting at work I get the splash screen and the keyboard stops working after the screen login. Then what I do is:
1) Open an APP get it ready to type in,
2) Close the keyboard completely until the IPAD shuts off
3) Open the keyboard again and it works
Annoying, but works for me.
At one point I was disconnecting the key board and reconnecting it, then closing it and opening it again as described above and it worked fine too, but was too much pain, specially during the start of meetings, until I discovered the simple three steps above. I hope it works for all until Apple makes the fix.