A method and apparatus are disclosed from the perspective of a network. In one embodiment, the method includes the network transmitting a Semi-Persistent Scheduling (SPS) configuration to a User Equipment (UE) for configuring a second Physical Downlink Shared Channel (PDSCH). The method also includes the network transmitting a configuration to the UE for configuring a first monitoring occasion for a first Physical Downlink Control Channel (PDCCH) and a second monitoring occasion for a second PDCCH, wherein the second PDCCH is associated with the first PDCCH. The method further includes the network not allowing the first PDCCH and the second PDCCH to schedule the UE with a first PDSCH partially or fully overlapping with the second PDSCH in time domain, wherein a last symbol of a later monitoring occasion among the first and the second monitoring occasion ends less than a processing threshold before a starting symbol of the second PDSCH.