Most home bakers spray the tops of their loaves during the first five minutes of baking. Now with rye loaves this can create problems.
Rye flour, though having a great taste, is not very big on gluten, so it is quite often mixed with white bakers flour so there is some rise and openness to the crumb of the loaf. The rye loaves usually don’t rise as much as a white loaf due to the overall weakening of the gluten structure from the rye flour.
In the following two pics of two loaves made with 1/3 rye flour,you can see the loaf on the left has opened up nicely, it was not sprayed.
The loaf on the right was sprayed with water three times in the first five minutes of baking. You can see a tear in the left hand side of the loaf that occurred very early in the bake. This was due to the already weak skin being further weakened by the water spray. As a consequence the gas, which would normally raise the loaf, escaped, and the softened loaf spread.