NxLog not even attempting to sync first few lines

I have a im_file to om_tcp route on the community edition.
My applications starts generating logs at 5am and runs every 15 minutes.
I have observed that it essentially skips the first X lines and syncs things only after the x lines starting 5:15 and works fine throughout the day.
There is nothing in logs at 5am.
I have tried routing it to another om_file on the same machine, it works ok.

Can you please help me fix it?

Here is the config:

AskedJuly 16, 2020 - 4:12am