The bug
Clicking on the recipe for coloring a white bed, which is available for the 2 * 2 crafting grid as well, selects the recipe for creating a bed. This can result in planks being placed in your head and chest armor slots if you only have the 2 * 2 crafting grid open.
Linked issues
is duplicated by 9
4 more links
Note the most likely reason for this: in the 3x3 crafting grid, the recipe guide shows two beds, one for the planks-and-wool recipes and one for the bed-and-dye recipes. In the 2x2 grid, you only see one bed icon in the guide, and click-holding displays the recipes only for the bed-and-dye versions - which can be crafted in a 2x2 grid. So the problem isn't that it's being displayed - it should be displayed - the problem is that clicking the icon directly uses the alternate recipe, the one with planks-and-wool instead of the bed-and-dye version it should.
Note that it *also* uses the wrong, planks-and-wool recipe when you click on the bed in the 3x3 crafting guide - as in, it uses that recipe no matter which bed icon you click, even if it's the one grouping the dye-and-bed versions instead.
TL;DR: A more accurate description of this bug is that clicking the bed in the recipe guide always uses the planks-and-wool recipe, even when it's representing the bed-and-dye recipes instead.