I think this is caused by merging Beauty pass with Bloom or Glare by the “Screen” function - I was getting the same results in Nuke when of the merged part was over <1
To me it looks more like the lowered threshold (so that “not very bright” things will be processed) combined with a very high Bloom amount of 10. So, my feeling is this is correct for that bloom and glare settings and it’s just that the settings need adjusting.
(a with / without comparison wouldn’t go amiss too)
Well, lowering the threshold and intensifying something 10x may result in overburn. 
And if you mean the purple saturated spots, that’s probably a result of Corona using the wide-RGB color space, which has to be displayed in sRGB on the monitor. The solution would be to either apply a LUT (Kim Amland’s ones should help), or to change the color of the offending object to a less saturated one.