After the upgrade to NoMachine server v8.9 or with a fresh new install of that version, opening an application when connected to the physical desktop or inside the NoMachine virtual desktop gives error:

ERROR: ld.so: object '/usr/NX/lib/libnxegl.so' from LD_PRELOAD cannot be
preloaded (cannot open shared object file): ignored.

Problem doesn't occur in custom sessions, or with previous versions of NoMachine.

A slightly different error is shown when running a 32 bit app on a 64 bit system and Gnome is using the X11 backend:

Error:ld.so:object '/usr/NX/lib/libnxegl.so' from LD_PRELOAD cannot be
preloaded (wrong ELF class ELFCLASS64) ignored

The LD_PRELOAD variable should be purged when the desktop is not running with Wayland.