I personally believe that you're right. More precisely, it was so "obvious" to me that nested <>'s would behave "correctly" in connection with local, that I was sure your test was flawed. So, to be sure, I reproduced it... only to find it miserably failing, albeit in a completely different manner:

picard:~/tmp [21:23:31]$ ls
file1  file2
picard:~/tmp [21:23:37]$ cat file1
line1
line2
picard:~/tmp [21:23:42]$ cat file2
line1
line2
picard:~/tmp [21:23:44]$ cat ../domk.pl
#!/usr/bin/perl

use strict;
use warnings;

while (<>) {
    chomp;
    print collect( $_ );
}

sub collect {
    local @ARGV = @_;
    join '', <>;
}

__END__
picard:~/tmp [21:23:53]$ ls file? | perl ../domk.pl
Can't open file1: No such file or directory at ../domk.pl line 13, <> 
+line 3.
file2
[download]

This is perl 5.10.0, and 2-arg or 3-args openedness of ARGV apart, I would definitely consider both the above behaviour and "yours" buggy. That such constructs are rare enough for me to only have discovered it now, after many years of Perl programming, does not make it less so.

I was about to send this post already, when I though that perhaps I should have localised the whole of *ARGV, which would have made things even more clumsy and counter-intuitive, but at least working: let me tell you that I tried and this appears not to be the case.