We just upgraded to 10.4.2, and the same full scan/sec trigger is now firing.
Ours is doing >500 per second - something is not right (30,000 elements across 4 pollers).
The database server seems to be handling it - but its a very large multi-core machine running SSD drives.
The node details screen is very slow to display - other screens are ok.
I'll log a case on Monday and see if we can work out what the cause is.
Dave.