This solution saved my life. However, if you try to clear all slides from the destination PowerPoint after cloning them from the source, an error alert will still appear. To avoid this, you should copy the slides first and then delete the ones you don't need at the end of the process.

https://learn.microsoft.com/en-us/answers/questions/539472/getting-a-repair-error-when-copy-slide-from-one-pr