AssetLifeCycle status is not a CMDB attribute. CMDB Audit will not capture this.
Did you try auditing AST:Attributes?
When ever you add new fields in Asset forms, add them first in the AST: attributes forms and then copy them over to the class you want. From there you can enable the audit functionality, once you enable the audit you should be able to see the audit in LifeCycle audit in the asset classes.
The field Status is already audited as part of AST:Attributes. Also in AST Join form, it works fine.
The audit does not work for the form which is self join of AST Join form.
The record gets created but GUID blank in CMDB Audit log form.
Yes. AssetLifeCycleStatus is already part of AST:Attributes and audited.
Issue is only in the custom self join form on top of AST Join form.
I understand from this page that Log should work fine even on Join forms. If this is not the case my advice is that you open a ticket with ARS Support, they handle ARS Audit.