In short - no.
I am fairly confident that the wrong values you are seeing are not errors coming from the DS18B20 sensor, the data from the sensor is protected by a checksum and if the data itself were being corrupted in transit, the checksum would surely fail.
I think your first suspicion - that it is something external that happens at the same time each day - is the likeliest explanation, but it might not be on your premises, it could be mains-borne.
I hope it’s a silly question - you, or someone within radio range, don’t have another node with the same ID also sending temperature data? There is nothing to prevent that from happening, so although highly unlikely, it is possible.