This may not fix the issue.. but its a quick step and worth the shot.. It may improve the color density by helping the ink fuse / fix to the paper better.
Also, could you print this page..
If only one color has the issue. Then we just need to replace that color.. Hopefully, thats all we need to do.
because if those steps dont work. Replacing the drum is in order. And I wouldnt expect you to have to pay for that expensive part yourself since the printer is barely 60 days old.
Below is the customer service contact number and hours for brother. If it comes down to this being an issue where the drum needs to be replaced, or the fixing unit. And its looking like one or the other at this point. Then the number below is where you want to start to find out how to submit the printer for a free warranty repair.
M-F, 9:00am to 9:00pm Eastern Time
Again though.. Id still like to try the setting change, and print that test page. It could just be a bad cartridge or cartridge fault. If we can repair this together that will save you from going without the printer during the shipping and repair process.
Senior Technician and Network Switching Systems Operator / Maintainer.