On Magento CE 1.9.2 we have been having this strange problem:
I will add products to a category, reindex, flush cache, check on front end, etc and the next day, some (not all) of the newly added products will mysteriously vanish from the category, no longer listed under that category on either the front end or the back end.
The first time it happened, I assumed that I had just screwed up, so I readded the products in the Manage Categories section and made sure to reindex. The second time, I added the categories to the individual products manage categories and then reindexed. The third time, I thought maybe I had to check that the products were both added on the Manage Categories section of the back end AND the manage categories section of the individual product page in the back end. So i dutifully did that, and reindexed after the changes to the categories for each product. It didn't help. Nothing has helped. The products refuse to stay in the categories.
More frustratingly, it appears to be a random selection of products, but once it starts disappearing it is the SAME products each time. I can't seem to find the common denominator as to why it affects these products. All are simple products and have been listed in other categories for months.
Every product that has had this issue have been 1.) assigned to at least one other category (that it remains listed in) 2.) Assigned to a store view 3.) is in stock 4.) has a quantity
The categories are not being asked to hold more than 1000 products ( in fact the categories that have products mysteriously disappear are supposed to list a measly 30-50 products), so it should NOT be related to the tables going over limit.
This has started recently (as far as I can tell), and the only change (besides making some new categories and trying to rearrange products to fit into those new categories) is getting the Magento cron.sh to actually run so we could get the transactional emails to work correctly (the cron job was apparently never set up when the store was set up - it's a long story...). I can't imagine that the cron job could be the root cause of this, but i could be wrong.
We do use extensions, but again, this is a fairly recent problem, and the extensions have not been touched for several weeks. It seems unlikely that one would suddenly start doing this.
EDIT:
I found out today that it's also ADDING products to categories semi-randomly now. A disabled category that was empty yesterday now has several products in it as well as other active categories having unrelated products in them, which looks bad to customers. I'm unsure how to even begin approaching a solution to this problem.
