Font rendering bugs in Acrobat?

I'm getting some strange display artifacts in PDFs opened with Acrobat DC and Reader DC, both version 18.011.20038 on macOS 10.12.6 (Sierra).

1) The ends of italic "s" and the bottom of italic "t" set in Charter (.OTF version 11.0d1e1, included with some versions of macOS) are smeared and too thin. There may be problems with other glyphs, I haven't checked extensively. Attached is a screen grab of the same PDF seen in Acrobat DC (top) and Apple Preview (bottom), set in 12/15, seen at 150%.

The same artifacts are visible at 100% and other sizes. The PDF was generated by Mac OS 10.12.6 Quartz PDFContext, PDF version 1.3 (Acrobat 4.x), from Apple Pages, but the same artifact appears when exported from Word 2011 via "save as Adobe PDF", Acrobat PDFMaker 15 for Word, PDF version 1.3 (Acrobat 4.x).

2) Although hard to detect in the Charter example, not all characters are aligned along the same baseline (see the "r" in "conversations"). This occurs in other fonts too. Here is an even worse example, of Melior in a PDF generated from QuarkExpress 8.15 engine, PDF version 1.4 (Acrobat 5.x). The top image is a screen grab from Acrobat, the bottom from Preview. You can see the wonky, jumping baseline especially in the "and" at the end of the first line and "trans-parency" in the last two. Again, it occurs at different sizes: I tested from 75% to 200%.

3) I also noted how much darker the same face (no matter which font) is in Preview than it is in Acrobat. It's almost like a semibold or regular vs. light! This makes it difficult to settle on the appropriate face for texts read as PDFs because they display so differently in different apps. These faces have the same darker rendering as found Preview, which I actually prefer, in other apps on macOS such as Safari, Chrome, Firefox, Word, Pages, etc. The rather light rendering in Acrobat in macOS appears to be similar to Acrobat in Windows, with Edge and Firefox on Windows rendering slightly darker than Acrobat but lighter than macOS. I assume this is just different font rendering technologies, but if there is any way for PDF producers to create a more standard display, I would like to know! (I'm on a 2014 retina 13" Macbook Pro, and checking/unchecking "font smoothing" in the General system preferences pane doesn't do much.)

TIA for any insights.