Is that tailwalking?
I tought tailwalking was more when the board starts to oscilate from right to left and lift you over the water and the fin. The board nose doesn't raise much more than the back. You will get the nose up if you open the sail tough. This is how I get out from this.
This is caused by too much lenght of fin and maybe by a flexible fin too. (7.5 sail, gust of 30kts on flat water, 46 cm fin on 135l freeride board). Switching to a 40 fixes it.