27.4.4.2.5 Timer Period < CCPxRB

If the value of the CCPxPRL is less than that of CCPxRB, but greater than CCPxRA, only one pin transition will be generated until the CCPxRB register contents are changed to a value less than or equal to CCPxPR. No Output Compare interrupt is generated (Figure 27-17). This condition allows the module to produce a 100% duty cycle output.