When I debug the issue I found it is coming from LLBLGen Dlls only.
Currently we are using version 4.5.3017.
I tried upgrading the LLBLGen dlls from version 4.5.3103 downloaded from MonoX site.
Upgrading LLBGen Dlls didn't worked, and we can not upgrade complete site as lots of changes has been done in the application related to our business.
I found source of the error is from dll : SD.LLBLGen.Pro.ORMSupportClasses.NET20
Please suggest if there is any other way to identify or rectify the issue.