I recently regenerated class diagrams that have been used for years in documentation. Unexpectedly, the rendering is now a very tall image, instead of an almost square one. Vertical lines between classes are long without any reason.
I tried to downgrade plantUML to versions that were known to work (2017.15), and also to downgrade graphviz (from 2.40 to 2.38), to downgrade java (from 1.9 to 1.8), to no avail. The same behaviour occurs if I generate the diagrams using maven plugin or eclipse plugin. I run everything on a Linux computer running Debian stretch. I don't know when the rendering changed, but it was sometimes between November and now since last release of my software was made on November and the diagrams were generated properly. The correct rendering that was generated on November can be seen here: https://www.orekit.org/site-orekit-9.1/architecture/estimation.html. The source diagram can be seen here: http://www.orekit.org/forge/projects/orekit/repository/revisions/master/entry/src/design/orbit-determination-overview-class-diagram.puml.
The image for the overview class diagram (the second in the page, in the "Least Squares" section) was 548x841 in November and now is 474x1787, more than twice as tall. The source of the diagram did not change at all, I simply try to regenerate the same image.