I'm no expert, and in no particular order: It could be something with the R5 hardware, it could be interference from nearby transmitters, the antenna setup, distance from what you're trying to monitor, or a random menu setting. Really hard to say without more details.
What step size for the AM band are you using? Are you using VFO mode to search or are these programmed memory channels? Can you share more about the frequency or location you're trying to listen to?
Also, have you tried doing a partial or full reset (assuming you've backed everything up) to see if that helps? See screen shot attached from the R5 owner's manual...
Running airbsnd but still the same outcome
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