I found mistake on API method  https://www.zoho.com/crm/help/api/searchrecords.html

After changing the lead, I still get as a result of some time with changed lead (it no longer fits the search criteria and stores a field with a modified value).

For example:

Lead#1 (MyCustomField=aaa), Lead#2 (MyCustomField=aaa).

Request:  https://crm.zoho.com/crm/private/json/Leads/searchRecords?authtoken=AuthToken&scope=crmapi&criteria=((MyCustomField:aaa))

Result: Lead#1 (MyCustomField=aaa), Lead#2 (MyCustomField=aaa). - is ok.

Change MyCustomField to "bbb" in Lead#1.

Request:  https://crm.zoho.com/crm/private/json/Leads/searchRecords?authtoken=AuthToken&scope=crmapi&criteria=((MyCustomField:aaa))

Result: Lead#1 (MyCustomField=bbb), Lead#2 (MyCustomField=aaa). - hey what does here Lead#1 ??

Very quickly make request:  https://crm.zoho.com/crm/private/json/Leads/searchRecords?authtoken=AuthToken&scope=crmapi&criteria=((MyCustomField:bbb))

Result: no data.

After some time, I've trying request:  https://crm.zoho.com/crm/private/json/Leads/searchRecords?authtoken=Auth Token&scope=crmapi&criteria=((MyCustomField:aaa))

Result: Lead#2 (MyCustomField=aaa) - is ok.

And request:  https://crm.zoho.com/crm/private/json/Leads/searchRecords?authtoken=AuthToken&scope=crmapi&criteria=((MyCustomField:bbb))

Result: Lead#1 (MyCustomField=bbb) - is ok.