11.5.1 CLRWDT Considerations (Windowed Mode)
When in Windowed mode, the WWDT must be armed before a CLRWDT
instruction will clear the timer. This is
performed by reading the WDTCON0 register. Executing a CLRWDT
instruction without performing such an arming action will trigger a
window violation regardless of whether the window is open or not.
See Table 11-2 for more information.