Some commands are different between verticals or versions of Autocad.
When certain commands (for example EXPLODE) are issued last in the Lisp routine, they may not behave as in a previous version. The workaround is to add (initcommandversion 2) before the command is called. Example:
(setq ss (ssget))
(sssetfirst ss ss)
(initcommandversion 2)
(command "_.explode")