Uniden uh037sx-nb sound emitting problem

Hello

Today I bought the Uniden uh037sx-nb which comes in a pair.

One of the walkie talkies is emitting a static sound around every 5 seconds which lasts for one half a second.
Once around 5 seconds has passed it emits it again for half a second and it keeps happening.

I notice sometimes it does not happen after using it for a long amount time.

It sounds like TV static. Sometimes it can be faint or sometimes it can be quite loud(when the volume is max its quite load).
Sometimes after the person has talked and has let go of the button it has and its quite loud.

Should I return them back to the store for a replacement or is this a normal?
I can deal with it but I just got them to day and expect them to work.

Thanks.

Any luck with this problem? I am facing the same issue.