MacBook Pro rebooting after disconnecting from both of my external monitors

I have two 2021 MacBook Pro 16" (touchbar), one personal and one for work. I dock them both vertically, hinge side up and connect them to my MSI 32" monitor and Samsung 34" monitor. The MSI is connected via USBC-DisplayPort and the Samsung is strictly connected via USBC and also powers my MacBook when connected. Only recently have both MacBooks been seemingly shutting off or rebooting (not sure which) when I unplug them from both of my monitors to use the other. I know this because when I plug them back in, I either have to now first open the macbook to log back in vs just simply connecting the USB-C ports into the computer, and all of my windows/apps restart upon entering my password (again, happens to both MacBooks). Does USB-C connection cause this with MacBooks? There is no noticeable reason why this would be happening to both of my Macs.