Explanation of the error
This Salesforce validation error that Gearset is surfacing is likely to occur on the "Asset" Custom object metadata type:
An example of the error message in our app would look as below:
"ControlledByParent is not a valid sharing model for Asset"
In the use case we've investigated, user tried to deploy changes from one Salesforce org to another.
In this particular scenario, user said that Sharing Rules were identical between the two orgs.
Resolution
Workaround that helped with resolving this error was to change the Asset Sharing Settings in the target org from "Controlled by Parent" to "Public Read Only".
In your Salesforce org you can find this setting in Security > Sharing Settings > Edit.
This allowed the deployment to happen without the error.
Useful resources
For guidance on how to amend Asset Settings check Salesforce documentation:
More information on a possible resolution to this error can be found here:
Disclaimer: This error is returned by Salesforce directly, rather than Gearset. Even so, we offer guidance based on our combined experience with the Metadata API. Where possible, we try to help guide you to fix or avoid this error. In the case that this isn't possible, we may need to direct you to Salesforce support for further clarification.