Responses
Yes but Chase knows Josh is holding out for his son's other parent. Who else who he hold out for if not the one who marked him? And the only one who could've ever marked him is Chase because he can have frequent sex with Chase without problems.
Him not instantly questioning how he can have sex just fine with a marked omega. Unless that's in the next chapter

Chase getting 500 hints to being Josh's baby daddy and still not clocking it
• Josh is an omega
• Josh has a C section scar and a kid
• Chase is the only man Josh has slept with
• Josh is marked but is suspiciously very sexually receptive to Chase instead of freaking out from his pheromones