I found a strange problem.
I have added a custom field to Relevanssi search scale and one value of this field is 5840-01-7 5-(Hydroxymethyl)furfural. When I use furfural or other letters to search, the result includes this value without any problem. But when I search the number such as "5840" or "58", it does not display in the search result.
I try some other fields by adding some number to them, the same problem happens.
What is wrong with it?