Perl: libapt-pkg-perl AptPkg::Cache->new strange behaviour under precise

I have a very strange problem with the constructor of AptPkg::Cache object in the precise package of libapt-pkg-perl (v. 0.1.25).

The perl script is designed to download a debian package for three different architectures (i386, armel, armhf). For each architecture I do the following:

1. Configure AptPkg::Config '$_config' with the right parameters and package-lists for the desired architecture.

2. Create the cache object with AptPkg::Cache->new .

3. Call the method AptPkg::Cache->policy to create the AptPkg::Policy object.

4. Call the method AptPkg::Policy->candidate("program-name") .

5. Download the package for the selected architecture.

This works very well with Ubuntu Lucid, but with Ubuntu Precise I can only download the package for the first architecture defined. For the other two architectures there will be no installation candidate (method AptPkg::Policy->candidate("Package-Name") doesn't return an object).

I tried to build a workaround and I found one solution how the script works for all three architectures, without problems, in precise:

If I create the cache object (with AptPkg::Cache->new) twice in a row it works and the script downloads the debian package for all three architectures:

my $cache = AptPkg::Cache->new;
$cache = AptPkg::Cache->new;

I'm sure that the problem has something to do with the method AptPkg::Cache->new because I checked everything else, what could cause the problem, twice. All config-variables are set correctly and I even get a different Hash for AptPkg::Cache->new for each architecture, but it seems that I am overlooking something important.

I'm not very familiar with perl, so I am asking you guys if someone can explain why the script works with the workaround but not without it. Further it looks quite strange if you have the same line of code twice in your script.