Unable to export quality png after 2018 update

[Niccosy]

Last night I was using Ai to create some simple math figure and it was fine exporting png
Then today, after the update my exported png all look like crap.

it was default 300ppi when I was exporting png by AI 2017, but now its default 72ppi at AI 2018.
Even I change the setting back to 300ppi , the outcome png still looks like its a 72ppi.

[Monika Gause]

There will only be 41 pixels in JPEG either.

[RLaw59]

If that's the case why do I see other identity plates that are look so much better (Personalize identity plates and module buttons in Lightroom Classic CC )? Not a big deal but I figured that if LR was making something available it would execute a solution that looks good...

[Monika Gause]

Less detail in that one.

You also might want to ask over on the Lightroom froum as to how to optimize it.