This is normal. Food contains lots of water. When you heat up the food, that water gets driven off the food in the form of water vapor. This is especially true at high temperatures.
The Anova Precision Oven vents this excess moisture the same way, regardless of whether the cook settings have steam enabled or disabled.
Note that this same phenomenon happens in a normal oven, too, except those ovens spread the vented moisture out over a much larger area so it typically isn't as noticeable