Calling block_list() drops Quick Tabs block to last position

I'm working on an issue with our Fusion Core base theme (#603644: Quick Tabs Block Order) in which Quick Tabs blocks get dropped to last position below/behind any other blocks in the region, regardless of their assigned position/weight.

The culprit appears to be the block_list() function. Whenever it is called on a region that contains a Quick Tabs block, it causes the block to get dropped to last position.

I can replicate the behavior in a non-Fusion theme (e.g., Garland, with a Quick Tabs block in the left sidebar set to first position ahead of other blocks) with the following code in template.php:

function garland_preprocess_block(&$vars) {
  $list = block_list('left');
}

Unfortunately, I'm not sure what I can do to work around this issue since I need to get a list of blocks in order to get a total block count for some layout formatting. In addition, I've seen other code use this function in order to add first and last classes to blocks.

Any ideas on how to fix/get around this?