I have the same problem - no so no Page Break after.

I solver the page break problem by turning OFF the Page Break After on the tablix and instead add a rectangle with page break after set to true.

But... there is another problem with this.

When exporting to Excel each Excel tab is named after PageName of the tablix.

If no data in the tablix, Excel uses the PageName from the previous tablix as the name (with (2) appended to the name).

I think the only way to deal with this is to have the query return an empty row when there is no data.