The two clocks reported are considered related and timed as synchronous by default. However, the timing engine cannot determine a common period after expanding the waveform of both clocks over 1,000 cycles. In this case, the worst setup relationship over these 1,000 cycles is used for timing analysis, but the timing engine cannot ensure this is the most pessimistic case.
This condition typically occurs with clocks that have an odd fractional period ratio.