Yes. One of the advantages of buying + selling beats online is the low cost. Rather than only sell beats exclusively for huge sums of money, producers lease beats at lower prices, meaning customers get great prices, and producers can still earn a living.
This means that if you're leasing a beat, there's every chance that others will lease that also. This is very common in the music industry, right up to top artists, and is nothing to worry about.
To ensure that no one leases the same beat as you, you can buy the exclusive. When bought in an Airbit store, it is automatically removed so it cannot be sold anymore. (Other platforms may not do this, so if buying the exclusive outside of Airbit, double-check this first). One thing to keep in mind is that anyone who has leased the beat before you buy the exclusive can still use it within the terms of their license.