i feel that my camera struggles with reds (t3). a frame-filling red flower is worst case. they seem to come out really saturated with less than ideal gradation? Blues i feel are a stong point. part of the problem may be that i do not fully understand the relationship between vibrance and saturation in lightroom. I feel like vibrance is how colourful things are, and saturation is how much colour is in the colourful things, if that makes sense. some of these pictures i turned the vibrance up to combat the grey overcast, and the saturation down a tiny bit to combat the red getting messed up. i usually leave saturation alone because it screws up blue skies very quickly, and use vibrance to get richer colours instead.
tldr: camera struggles with red, but it could be my hamfisted post processing as well.