Error 500310 context: num_tuples != 0

Hello. Redshift DB, when making a simple request, I get an error, the reason for which is not clear to me. What could be the problem?
It seems to me that the problem is in the event_timestamp field, but not sure. event_timestamp BIGINT ENCODE az64, only digits, null values are allowed.

SELECT count(*) 
FROM sa_analytics.events  e
WHERE
   e.client  IN ('25af4d33-991b-4734-bfb5-71c84a131c4e','fbdc9c91-c99e-41eb-8ff8-70146f0fced5')
   AND event_timestamp >= datediff(ms,'1970-01-01',(current_date - interval '24 hours')::date)
   AND event_timestamp IS NOT  NULL ;

  error:  Assert
  code:      1000
  context:   num_tuples != 0 - 
  query:     14198439
  location:  vec_fetcher_az64.cpp:291
  process:   query0_125_14198439 [pid=17070]
  -----------------------------------------------;