This behavior occurs in connection with a set "lower" soft limit UL_L > 0 or IL_L > 0.
As the value "0" for USET or ISET is nevertheless permitted as a special case, the desired setting range can however no longer be reached from "0" via incremental keys [ ] or incremental rotary encoders.
It is possible to temporarily move or delete the lower soft limit limits. However, the simpler way is the numerical value direct input (numerical keys) with jump to a permissible value > UL_L or > IL_L.