I have flown a lot of survey towing a bird and using radalt to maintain AGL and can say that sometimes they do strange things usually solved by trouble shooting the antenna and wiring to the instrument.
On another job when approaching a certain airport we would usually get a false radalt warning for a few seconds on long final. We were flying over flat jungle terrain. We looked and looked but couldn’t find anything that would trigger a warning. We were at about 500 agl over the spot and radalt was set to 150. We used to refer to it as the “Tall Tree Checkpoint”
I have also seen radalt start painting the sea floor and not the water surface. Usually over shallow, clear glassy water over a flat sandy bottom with no swell.
In the case above I can see no reason why the pilot would become “Unsettled” and abort the flight because of an erroneous radalt warning while in VMC conditions.