@yourfriendkarol that's intresting, sounds like possibly something in your code. I have not experienced similar issues myself. You'll need to track it down by adding logs on every place and combing through them to find where inside the bot its breaking.
Other possible thinking is the usage, if all 8 bots are running on one machine. How many actual browser threads are being used in total? Have you tried changing the browser settings to launch only [ X ] if available cpu/ram is below/above a certain amount.