Why does the bump not work in the lower example? It seems simple enough: a checker map being used in a CoronaMix as ‘mix’ between black and white.
Because it’s max’s “feature”. Bump is treated differently than other slots and has tons of limitation. If possible, try to bake your bump maps and then plug them as bitmaps.
Hmmm, I did know of the limitations of Max bump in it’s own renderers, though I didn’t realise that extended to other renderers too.
Thanks.
Yup, try using color correction with a bump map. 
I still don’t get this part either :- ) Corona has the best integration within 3dsMax alongside Vray, I guess that comes with its own drawbacks.
maybe, a note “coronamix doesn’t support bump” just like in coronaoutput would be useful.
but in https://corona-renderer.com/bugs/view.php?id=303, ondra said limitation was added. but sorry, I don’t understand about what “added limited support” is..
it means the support was added to the basic modes, such as add, subtract, multiply
but, now bump still doesn’t support coronamix even with the basic modes you mentioned.
I hope don’t misunderstood something