It also happened to me at the moment I touched Viber.
I use google translator because I don't understand English
Laptop Asus GL503VD, I had BSOD twice with cldflt.sys error when updating Viber desktop, no tips in this forum helped me. I did a factory reset of the laptop. After reset in safe mode using DUDU v18.0.19 I uninstalled the Nvidia driver and installed the latest 441.20. Yesterday was the last Viber update and BSOD did not appear, I think I fixed the problem. I'll be happy if I helped someone, hello.
The BSOD no longer appears.