I've got the problem with my MacBook Pro (2016, 2 Thunderbolt 3 ports), I've connected two adapters (both HDMI, Ethernet, 3x USB) to Thunderbolt ports, so basically my mac is a kind of dock station and I'm using only externals monitors. I started using the wireless Logitech K750 Mac keyboard, USB Logitech Unifying Receiver connected to one of the adapters. I noticed that sometimes the written text appears with a long delay and it's a bit unpredictable sometimes it works well, sometimes it works horrible and lagging so much... The distance between the unifying receiver and keyboard is about 10 centimeters.
The USB keyboard works very well, there is no delay/lagging at all. I have the same K750 keyboard but version to Windows (on Windows it works perfectly), but on Mac same situation, lagging so much.
I recently started using the Mac and I have no idea why is this happening. Does anyone has a similar issue and fix it? Let me know, how I can get rid of this.