In database discovery there is an item "Checksum failures".
It has 2 preprocessing options, JSONPATH and CHANGE PER SECOND.
It is possible that DB returns value NULL for checksum failures, in this scenario item preprocessing fails and item becomes unsupported.
In addition, because other parameters are changing in the master item, this ends up filling log files with long error messages, because the error text changes every time.

Please add another preprocessing step to validate the data or even replace NULL with 0 to avoid this.