Alright, apparently there are more chrome parts that also bugged in the rain. For example, the 389 headlights, the footstep on the front fender, the airlines that sitting on the cab, some part of the deckplate, and a cylinder thingy above the front footstep (below the driver and passenger door). So this time, I checked the whole folders inside the automat folder instead. Basically, any .mat files that have this line :
reflection: 1 (or above)
I decided to change all the files with reflection above 0 to be 0. Hopefully this will solve all the issue of the weird chrome parts in the rain (or any other non-chrome parts that may also looks weird in the rain).
Credits:
Joko_P