Hello from Amazon Selling Partner Support,
 
We understand that you are seeking for assistance regarding your FNSKU: --- as it has 5 units that are in "Researching" status.
 
After carefully reviewing your FNSKU, we have confirmed that the 5 units in researching status.

This represents the misplaced or fulfillment-center-damaged inventory that is actively being confirmed at our fulfillment centers.

A timeline shows the duration of the research, which will never exceed 60 days. Once the inventory that is being researched has been reimbursed or has exceeded the 60-day duration, you will see the corresponding adjustment move to the Inventory Ledger report’s detailed view.

Hence, we advise you to kindly wait and keep this event monitored on your inventory ledger report.

For more information related to this matter, you may visit the help page below:

Inventory Ledger report
https://sellercentral.amazon.com/help/hub/reference/G4FKT5KQWFFJ7LDN