Precipitation lead time

Hello,

I use wet deposition and precipitation data with lead time 0. Checked the values (for example) No3 wet deposition with both large scale and convective precipitation have data in the file however total precipitation has no data(value) in the file with 0 lead time. downloaded slow access, single level meteorological. Additionally, I downloaded lead time 1 total precipitation then it has values. Why lead time 0 total precipitation doesn’t provide values??

Thank you for your comments and helps