blank Audio Engine output

When working in 8.5 today all my prefs.& setting were reset. I exported a (stereo) mix audio & when I went to do it again I noticed the usual L/R box wasn’t selected for the audio engine output. (none were selected)

I’m curious to know if there’s anything handled different in rendering between the two to a stereo mixdown. (None vs L/R selected.) Without any checked I assume it just goes through the main outs?