Search in a given product category - does not reflect all the items that match the query, where to dig?

Question

1C-Bitrix

Hello. There is a website, an online store on VPS (VM Bitrix). The essence of the problem is that the search in the specified category does not work correctly.
The request is formed by the name of the 1st word of the product name, in the search results it reflects only a part of the positions (not all that satisfy the request).
Empirically, the following pattern was revealed - when deactivating and reactivating goods in a product group - the search in these categories of goods works correctly (reflects all positions that meet the conditions). But after passing a certain number of categories, it stops working correctly in folders in which this operation was carried out in the order of priority before. There is a feeling that the index file is not set up correctly, or indexing does not work correctly after a certain number of products.
On this problem, it was also noted that when using 2 words in the search string, available in the name field, the search also works correctly.
Tell me where to dig, I’m ready to thank financially, the person who suggested the right decision

Answer 1

At a minimum, you need to look at the request code from the database. And is there a limit on the search, and in the code it can be random for the request. Maybe at the output, the code is needed here.

Answer 2

Make a complete re-indexing of infoblocks in the Search module.