Confluence 5.1. Sorry am not sure if it's 5.1.5 or earlier, we just migrated.

1. Insert Table Plus macro
2. Insert table within macro
3. Insert table within table, or as a second table within macro
4. Edit Table Plus macro settings so that "Multiple Table Processing" is turned off, change border setting to something obvious like 5px, or apply a custom class.

Expectation: The nested table and second table retain default settings. The first table has the border and class.

What's happening: All tables inherit the class and border setting of the Table Plus macro. Same goes for the second separate table. I did not test other settings.