Hi Guys,
I've just bought my iPad Pro today and one of these Logitech keyboards and am also coming up with the same issue.
But I think I have a resolution that may be of some use to you.
I've just gone in to the Settings menu (Settings > General > Keyboard) and disabled all of the keyboard settings from Auto-Capitalisation down to Enable Dictation.
This seems to have improved the responsiveness of the keyboard somewhat and it hasn't dropped a key yet.
So give that a go, and at least you should then be able to use the basics of the keyboard.
I'm thinking that as Apple update their software, if it has any impact on the iPad that makes it think a bit whilst you're typing then that is going to have an impact. So probably things like Predictive, Auto Correction, Shortcuts that might use a bit of processor power and cause it to think about each keystroke then might make it miss the following keystroke and so-on which is then causing the lag and missed keystrokes.
So my recommendation is for you to have a play around with the keyboard settings. Turn it all off, and then just turn on those items you really need.
This should then keep you typing whilst Logitech and Apple work together on a solution.
Merry Christmas.
😎