In dusty environment, clouds of dust can create temporal distance values. These distance values are changing from cycle to cycle. A mitigation strategy is to use method of removing flying pixels.
Royale viewer howto
Tools => Parameters => UseRemoveFlyingPixel_Bool
Royale SDK howto
See also: Unambiguity issues. High reflective objects could generate distance values outside of the unambiguity range. The use cases with 9 phases (MODE_9_…) have an unambiguity range of 7.5 m, the use cases with 5 phases (MODE_5_…) have an unambiguity range of 2.5 m