Hi!
I use 10 SmartLocks same time and 3 of them are Gen4 Pro and this 3 regulary go offline (release 4.1.8). I need to reset them every 2-3 days 
I have tried medium battery power setting, 2 differnt TP-link routers and Huaiway, also GSM, Coaxial and ADSL Modems from differnet providers A1 and Magenta, different WiFi settings main or guest network, with or without WPA. It is not helps.
The only way to make a stable connection is to use a Bridge.
The differens between “Gen4” and “Gen4 Pro” is a Wifi Option and 70 Euro.
I hope Nuki have a plan how to fix this Wifi issue with Gen4 Pro. Or they need to give free bridge for every Gen4 Pro because Wifi option actually does not works. Or call back all “Gen4 Pro” and replace them with “Gen3 Pro” (with them I dont have any problems).
@Nuki if I can help somehow to fix this problem - please let me know.