Large spaces at end of line and odd hyphenation

Since a few weeks I have an odd problem when I import Word docs into InDesign CC 2015 (both on my Mac with OS X 10.11.6). I create a magazine in which all text is left aligned. Usually InDesign does a good job on filling each line and using hyphenation when needed. However, since a while I notice the space/gap at the end of a line if often larger than needed and words are being hyphenated without any reason. So a word that would fit perfectly well on a line is hyphenated, leaving a large space/gap at the end of the line. So lately I have to add forced line ends all over the place to solve this. Or I have to force hyphenation manually.

I didn't change any settings in InDesign regarding this. Anyone ever seen this before?