Buggy rendering when table is at very top of buffer

[Lenbok]

I have a buffer (in orgtbl-mode) containing this:

| panel_id | gs_use | species_id |
|----------+--------+------------|
|        1 | false  |          1 |
|        2 | false  |          1 |
|        3 | false  |          1 |
|        4 | false  |          1 |

which renders like this, with a buggy header divider line:

If I insert a blank line at the top, like so:

| panel_id | gs_use | species_id |
|----------+--------+------------|
|        1 | false  |          1 |
|        2 | false  |          1 |
|        3 | false  |          1 |
|        4 | false  |          1 |

I get the expected rendering (although with the extra blank line at the top):