Is there a reason two interstellar objects were found in the solar system in such a short period of time?
The biggest contributor to these two observations happening so close to each other is capability and interest.

Our ability to observe such objects is ever increasing.
Once we saw one, our interest increased and we looked harder ie. lots more funding for the necessary observations to be made that would identify such objects.
We saw the next one soon after.

There is unlikely to be anything special here, just the politics of scientific funding. 

It may be that these were two objects that coincidentally passed through the solar system at nearly the same time, but we are going to need to make many more observations of such events before making such a determination.