Hi - Yes. The solution is very simple.

Instance of your client

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1. cmdb_metadata_containment.list of instance with issues

2. Find the tables, related to the class with problem,

3 - Take a full backup in XML of your affect items (Recommended)

Your PDI

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4. cmdb_metadata_containment.list of fresh PDI with same ServiceNow version of your client

Instance of your client

=================

5. Export the records (via XML) related to the records of your CI Class you are having problem 

6. Import them records (via XML) to cmdb_metadata_containment.list

7 -  Retry Discovery from Discovery errors , it will fix all them.

If some errors still remains in the card,  just wait the OOTB runs the clean-up erros , and it will clean automatically the remaining errors. 

> https://XXXX.service-now.com/nav_to.do?uri=sysauto_script.do?sys_id=81c17c7467813300d88fa0119585ef6b

> <https://url.de.m.mimecastprotect.com/s/MUTBC6Wn4wIrr9mNMHmiLU56wpp?domain=csf.service-now.com>

Any other questions let me know 

Thank you