When the Rendering Preference under Page Display for Text Smoothing is set to “None”, Adobe Reader seems to be having issue when rendering certain embedded fonts (true type font for instance) at certain zoom level.
We first thought this was an Adobe bug but looking further into this issue, we found out that it was an issue with bitmap font tables being preserved by jWordConvert when subsetting fonts. We found today a weird issue in the way Adobe Reader DC and Adobe Acrobat render some embedded fonts at certain zoom level.