See if this happens if you change the font. I've just noticed a similar problem when we plotted using the helvetica font. Although we didn't solve the problem, we worked around it by changing the font to arial.
regards
Haneef
Haneef Tayob
Aziz Tayob Architects
AC23 INT rel 3003, OS X 10.14.6 iMac 3.3ghz i5 dual monitor, 24GB RAM