AFAIK object methods are not checked during compile time but caught runtime.

That's the case for all subs, not just methods:

>perl -e "$|=1; print 'this is runtime',$/; test();"
this is runtime
Undefined subroutine &main::test called at -e line 1.
[download]

It's a requirement because of perl's dynamic nature. What if I had done
*test = \&testing;
or
eval "sub test { return $var }";
earlier on in the code? If the check were to be done at compile time, test() would incorrectly be labeled as an error.

There's also the opposite case to consider, the case where the check passes even if the function doesn't exist, such as in
$func = 'test'; &$func();

Methods complicate things further. $obj->method() depends on the value of ref($obj) when that code is reached (run-time), the current (run-time) value of @ISA in a number of packages, and whether method currently (run-time) exists in a number of packages.

And then, there are modules with AUTOLOAD...