Just want to update my "long-term" test result in the last couple of days. It seems to have resolved the module-adding issue completely when I tried to relaunch the Packet Tracer app after I came back from work and turned on my Mac after a complete shut down.
This resolution seems to be consitently preventing the issue recurring effectively. However, there is a funny situation, which is when I try to use the module-adding function by drag and drop in the first launch of the packet tracer app after complete and clean Mac startup from the complete shut down over night, it tends to fail working. So, I quit and relaunch the packet tracer (without a complete shut down or restart), the module-adding function works magically without typing the umask 011 command int Terminal every time.
This solution can be proved effective. Massive thanks for the contribution!