Is it possible for the forward and reverse reactions to have different reaction orders? For example, in the case of non-dissociative adsorption, the rate of the forward process is given by

$$\frac{\mathrm{d}\theta}{\mathrm{d}t} = kCN(1−\theta)$$

where $C$ is the concentration, $N$ is the number of surface sites, and $\theta$ is the fraction of filled sites.

The reverse reaction is given by 

$$\frac{\mathrm{d}\theta}{\mathrm{d}t} = −kN\theta.$$

Hence, it seems like the first reaction is second-order, while the second is first order. This seems strange to me.
Why is this strange?

Consider:

$$\ce{2A &lt;=&gt;[$k_1$][$k_{-1}$] A_2}$$

Forward rate is second order: $k_1[\ce{A}]^{2}$.

Reverse rate is first order $k_{-1}[\ce{A2}]$.