Does anyone know why I’d be getting double spacing in my code block output (see below). It isn’t causing any issues but is annoying to look at. This is a new issue and I can’t seem to find an option to change it. Thanks! 
Is your own code generating the std.err output you posted? Are there aren’t any extra instances of the text \n in what you are sending to std.err?
Does it happen in a new notebook or after you restart the kernel? My thinking in asking that is because sometimes you can change the context settings earlier and affect other output later without realizing it.
Coming at this another way, do you see it happening with the following code pasted in a cell in a new notebook and executed?
import sys
sys.stderr.write("a\nb\nc\nd\ne")
The above should print four lines with a single letter on each.
Thanks for the help troubleshooting. It is in my code but seems like maybe more of an r issue with the message function but still can’t seem to get rid of it.
It looks to be tied to what you are returning from your dataframe with nrow I think. The message function normally doesn’t do that:
I wonder if wrapping your nrow call with trimws might help? (See https://stackoverflow.com/a/30210713/8508004 )