[exim] Limit to length of named lists

Is there a limit to the either the number of items in a named list or to
the actual length of a named list? I checked the documentation for this
and didn't see such a limit. The reason I ask is that some of my named
lists are getting pretty long. When I test using exim -bh the error is
that the list is too long and therefore truncated, but I am getting no
errors in the log.

Thanks a bunch.
Craig