Fully-framed tables are too narrow in PDF exports

[philippemilink]

With the following input:

The following table is correctly rendered in PDFs:

| Column 1 | Column 2 | Column 3 |
| -------- | -------- | -------- |
| A text a little bit longer in this column. And even more longer. | Text | Text |

The following table is incorrectly rendered in PDFs, it is too narrow:
+--------------------------------------------------------------------+------------+------------+
| Column 1                                                           | Column 2   | Column 3   |
+====================================================================+============+============+
| A text a little bit longer in this column. And even more longer. | Text       | Text       |
+--------------------------------------------------------------------+------------+------------+

And still some text

I get the following PDF:

The bug is in zmd 10 and 11.