Consider a space with a field of type 'map' and a secondary index over a nested field: ```lua appeals = box.schema.create_space('appeals', { format = { { name = 'session_id', type = 'uuid', is_nullable = false }, { name = 'agent', type = 'map', is_nullable = true }, }}) appeals:create_index('primary', { parts = { 'session_id' }, if_not_exists = true }) appeals:create_index('agent_id', { parts = { { field = 'agent', type = 'string', path = '.agent_id' } }, unique = false, if_not_exists = true }) ``` When trying to select tuples directly via box API on the storages, it works as expected:  When trying to select via CRUD API on a router, the request hangs: ```lua crud.select('appeals', { { '==', 'agent_id', 'denis.tulupov' } }, { use_tomap = true }) ```