On the front page of my website I have two blogs displayed. Basically by two copies of the same template file (not a skin).

This has been working fine, but I wanted to add categories to the blog entries. After the line

$Item->issue_date();

I added a line

$Item->categories();

This works fine on the first blog, but on the second blog I get an error from this line:

Warning: Invalid argument supplied for foreach() in /usr/local/psa/home/vhosts/submarine.org.uk/httpdocs/b2evolution/b2evocore/_class_item.php on line 309

It seems that something needs to be reset between the two attempts to process the blogs.

Looking through _class_item.php I wondered if this might be related to the category cache but I have no idea where to start to resolve this issue.