Hi high-spite,
Without knowing the project settings,
Here is my short demo:
pixel_1-10.jpg
The resolution you provided shows a 1:10 ratio, which means for a 2D object that is a hundred times more pixels in the hi-res than in the low-res. (I rounded your 1460 to 1500 for clarity.)
The energy (light) that a single pixel has in the high-res version, if no post effects are applied, can't grow over one pixel. It creates one pixel.
The energy (light) that a single pixel has in the low-res version, if no post effects are applied, can't grow over one pixel. It creates one pixel.
However, in the low-res version, that pixel has an area that is a hundred times larger. It will show different if both images are shown side by side in the same size.
This is the short explanation. Anything else, I need the file, reduced to the problem.
If it is larger than 1MB, then it can't be attached here as a C4D.
Please use a cloud service, but for security reasons, I will touch only Wetransfer, Google, Dropbox, Apple, or Adobe. Please paste the full URL into the text, no HTML wrapper. The file uploaded as c4d, no compression, no zip, and surely no rar. Sorry for the long request.
All the best