I did show how two clock sources could be diode OR-ed, but made no mention of their timing. I was not aware then that one source going high while the other source was already high might be a problem. That situation might require some sort of negotiation/prioritisation, depending on the intended circuit function. As you recognise, turning each source signal into a brief pulse could be the answer, since it would drastically reduce the chances of two signals overlapping.
But if, say, the latch is already set when two incoming pulses coincide, both are clearly intended to reset the latch, so does it matter which one causes the reset?