diffstbprobe cause sim fail

Hi,

I use diffstbprobe to check stablity of the loop. The sim got error info in the log as

"The instance `Idiffprb' is referencing an undefined model or subcircuit, `diffstbprobe'. Either include the file containing the definition of `diffstbprobe', or define `diffstbprobe' before running the simulation."

The issue disappear after I recreate netlist then run the sim. 

This happens regularly if I update the design, check and save then to run the simulation directly without recreate netlist independently in advance. 

I am wondering is there any specific point should be payed attention to this cell?

My cds version is: ICADVM20.1-64b.500.33

mmsim version is: 23.1.0.242.isr1

BR