This is on a fresh install of Leap 15 followed by all current updates.  The
hardware was previously very stable with Leap 42.3.

Various GUI applications fail for no obvious single reason.  This affects at
least firefox, google-chrome, VLC, and emacs-gtk.  All failures are while the
application is doing something.

The errors captured from the command line for firefox and google-chrome are:

     - firefox: Fatal IO error 11 (Resource temporarily unavailable) on X
server :1
     - ERROR:chrome_browser_main_extra_parts_x11.cc(62)] X IO error received (X
server probably went away)

This takes place while the system is under heavy CPU load.  The CPU is between
98-100% load with a large computational task at reduced priority.  Failures
occur at intervals from after a few minutes use to about an hours use, mostly
of web browsing.

When the heavy CPU load is removed, the error rate drops dramatically, perhaps
to zero.  No errors after 2 hours.