2080ti along with 1080ti, 1080tis are not detected

I had 2x1080tis, I just added 2x2080tis and upgraded the driver to latest (Ubuntu 18.04). Also I installed CUDA. Everything went well, cuda nvcc works, 2080tis are detected, but now it doesn’t detect the 1080tis anymore. What am I missing?

Please run nvidia-bug-report.sh as root and attach the resulting .gz file to your post. Hovering the mouse over an existing post of yours will reveal a paperclip icon.
https://devtalk.nvidia.com/default/topic/1043347/announcements/attaching-files-to-forum-topics-posts/