This is the "expected behaviour" with CEF 77+ under Linux (and perhaps macOS as well, but the viewer so far keeps using CEF 72 for the latter)...
This CEF bug has been
duly reported to the CEF developers, but they apparently expect me to fix it ! Like if I had any time available for this... They even flagged the bug as "minor" (I should perhaps do the same with viewer crashes, so that I won't have to bother and fix them ?...
)
You can safely ignore these crashes however (the viewer wrapper script even goes as far as to set the ulimit so that no crash dump will be written down and clobber your hard disk/SSD, thus why you did not get any): they won't prevent CEF to "work fine" (well as fine as this bloated piece of pure crap can work).