I had exactly the same problem described by @ibsoreal. I'm using a MacBook (macOS). Just as @Keith88 describes - I was able to remove the unwanted 4/4 by placing the cursor one beat after the time signature, and selecting "---" from the Time Signature dropdown. After doing this the second 4/4 disappeared. Thank you!

I'm using iReal version 2020.12 (201202).

-Dicentel