I have this problem where the catalog_product_index_group_price database table is flushed when I save a product. Only the product I'm saving is left in catalog_product_index_group_price.

After a reindex of the 'Product Prices' all group prices are regenerated.

When I change the setting of the 'Product Prices' indexes to 'Update on save' the problem does not arise.

Is this a general bug? Or am I having a conflict somewhere? I have not extended or overwritten any related core code.

Current version is CE