Me too, on multiple Roku devices, including a Sharp branded Roku TV and Roku Premiere Player model 3920CA.
I have just tried updating at least one of my clients to version 11.5 to see if that helps.
Roku had me uninstall the channel. Restart the device via Settings/System/Power (if there is no Power submenu, proceed to next step)/System restart. Then reinstall channel. Seems to have worked.
I don't think the reinstall is the answer. Updating the Roku to 11.5 seems to be the solution.
One thing I did figure out is that if you have 2 devices on one account, you have to remove Bloomberg on EACH device. After removing on one device (Roku Ultra in my case) it does disappear on the channel screen of the other device (Roku 3 in my case)... After doing a restart via "Settings/System/System Restart" on the Roku Ultra Bloomberg worked fine on that device. The Bloomberg Channel reappeared on the Roku 3 but it still had the audio problem.
After removing the Bloomberg Channel and doing the "Settings/System/System Restart" on the Roku 3 the problem was solved and the system updated to 11.5.0. That is new as I had tried updating manually earlier and it would not update saying system was up to date. In either case, either the update fixed the problem for me or the removing and reinstalling Bloomberg on each device fixed the problem.
I would just do the update to 11.5.0. That is easier and only takes a couple of minutes.