Indexes always in backlog

[mirkorap]

Hi,
I have a problem with smartcategory_product indexer. I need to sync a lot of products from a PIM to Magento. During the sync I see that the smartcategory_product indexer go in stuck and the smartcategories doesn't work properly (some products don't show in the smart category). If I disable the module, all work properly. I see also that this problem maybe is caused when I have a too nested categories. The structure of my categories is the following:

• Master catalog
  • Woman
    • Bags
      • Handbags
        • Tote bags

The problem is with the 4° level of nesting (Tote bags in my example). In fact if I expand the treeview of Handbags, I receive a 404 error from console:

http://172.50.0.10/admin_o35t7f/smartcategory/rule/categoriesJson/key/7e318a4e519498749fc91536bc31318ce956a87f31458af4818398e3b0cd24ab/attribute/category_ids/form/category_formrule_conditions_fieldset_328/?isAjax=true

The route smartcategory/rule/categoriesJson does not exists. Could this be linked with the indexing error?