SQL error when upgrading Org to Service Pack 1 (2016.01)

I'm trying to install the Service Pack to 2016.01 on-prem from here:

https://www.microsoft.com/en-us/download/details.aspx?id=52662

When I ran the installer, it said that some organizations (I only have one) were not upgraded, and that I should do so manually from Deployment Manager.  So I went to DM, selected my org, and tried to update.

This fails, and in the log I get the following:

Update Organization with Id=<snipped> failed with Exception:
System.Exception: Error.ActionFailed Microsoft.Crm.Tools.Admin.InstallDatabaseUpdatesAction ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Data.SqlClient.SqlException: Cannot drop index 'cndx_PrimaryKey_OpportunityProduct' because it enforces the full-text key for table or indexed view 'OpportunityProductBase'.
Could not drop constraint. See previous errors.

We have not made any weird manual changes to the database or anything, and we don't even use Products...

Any workarounds for this error?  Thank you!