How to stop "Site" Field from changing when changing templates

How to stop "Site" Field from changing when changing templates

Hello, 
Wondering if anyone else is having this issue or found a work around.

We have multiple Service Category and Incident templates setup and we have noticed when converting an incident to a service request or even updating one service request template to another the Base Site field will auto populate to "Base Site"( This will happen when we select "Overwrite field values with template values"  > Apply to all Fields Values. If we don't select these options then there are other fields we need to manually setup. 

Is there a way to stop this from changing ? The Site field should follow the site the requester has setup and I have not found a way to stop this in the template. I am not even able to delete the Site Field in the template to see if that would solve the issue. 

Thanks in advance. 

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