Any expression in Process Display Name throws exception

Question

Let is consider the scenario of 
 
 "TestPM1" have rule!Process_Display_Exp(ri1:"abc", ri2:"xyz") as an expression in its Process Display Name 
 "TestPM2" have "TestPM1" as a sub-process 
 In execution of "TestPM2", process gets struck at the point of initiating the sub-process "TestPM1"

"TestPM1" will never be instantiated rather display name will be displayed in the designer "All Processes" report with "Process_Display_Exp" UUID as follows
 
 =#"_a-0000dd66-1190-8000-9ba2-011c48011c48_32909"(ri1:"abc", ri2:"xyz")

Not only this rule, no rule works for any process model in Process Display Name. 
 Please let me know if any of you faced this? or know the solution?

Mike Schmitt · Answer

You might need to include more detail as to what's in your process display name rule - I have hundreds of process models whose process display names are expression rule based and they work fine.