[mathil]

I did some more reading today and I noticed the 'extra-wide letter spacing at the beginning of the line' problem that GeoffR reported, only once. It was on the second half of a hyphenated word. Turned off justification so that the word would not be hyphenated anymore, and the problem was gone. Changing to another font (built-in Amasis) also seemed to fix the problem. I will keep reading with the justification off and see if it appears again.

EDIT: Read some more with the justification off. In my experience so far, when the justification is on the first problem (extra wide letter spacing) appears very occasionally; when it is off, this doesn't happen but I see irregular spacing in some lines that is consistent with the second problem that GeoffR reported, and much more often.