SYMPTOM:
When performing a project comparison the user receives the following error and the project comparison does not finish successfully.

CAUSE:
This is a known issue in Strategy Object Manager 9.x.
The root cause of the error is that an object being compared has an ID with all numeric digits.
NOTE: It is extremely rare that an object ID will be generated and only contain numeric digits for all 32 values.
ACTION:
Issue has been fixed in 10.x, kindly upgrade to 10.x to take advantage of the fix.
WORKAROUND:
Create a copy of the object which has an all numeric object ID. This copy will very likely not be all numeric. Then remove the object with the all numeric ID and replace it with the newly created copy.