I am using ZCS 5.0.15. I have found that Search frequently fails to find all possible matches.
For example, I searched for email with M2H* in the Subject, in a specific folder using this query: subject: (M2H*) in:"inbox/Met-2/Luis Caturrini". (I used Advance Search to set up the search query.) That brought up nearly 100 emails which I then moved elsewhere. However, it did not bring up all matching emails. For example, an email with the following subject line, M2H-L2-main kitchen slab sleeves..., remains in the inbox/Met-2/Luis Caturrini folder. There are others as well. I can't see any difference (related to my query) between the selected emails and these others that were not selected.
I recreated and re-ran the search but, although I can clearly see it in that folder, the search still comes up empty. This happens with many, if not most, of my searches. I cannot depend on the search function to find all matches.
Any advice would be appreciated-- even if it points out some really stupid thing I may be doing! I need to be able to find all matches with my searches.