Thank you for your post.
I am unable to reproduce the issue using FileMaker Pro 16.0.2 under Mac OS X 10.11.6 (and macOS Sierra 10.12.5). This is what I have done:
1. I created a new database file with four Text fields: Name, Address, CityStateZip, and Phone.
2. On the layout, I created a Tab Control with two panels: Address and Phone.
3. I also assigned an object name for each panel: "Address" and "Phone".
4. On the Address panel, I put the fields Address and CityStateZip.
5. On the Phone panel, I put the field Phone.
6. I created two buttons, "Address" and "Phone" that execute a single step: Go to Object, selecting Address, and Phone, respectively.
7. In Browse mode, I added one record and manually selected the tab panel to enter the information.
8. I clicked the buttons many times to switch between tab panels. I never encountered content from both panels at the same time.
Let me know what I am doing differently than you so I can reproduce the issue.