Thanks for the report, Patrick.
This is actually a bug in the dependency Keyword::Simple.
I have reported the problem to the maintainer, Lukas Mai, but I do not
expect it to be fixed soon, as Lukas does not seem to have been active
with that module for some time now.
Meanwhile, I will investigate whether I can code some kind of work-around
into Keyword::Declare, though that may take me some time.
Once again, much appreciated.
Damian