One of the oldest problems with Autoplot's testing is occasional misfires, where the output yaxis range is slightly different than the normal result. I tracked this down to "scaleListener" in axis controller, which listens to the row and column and axis range changes to update the scale property.
Today it's test 149 which is causing problems:
https://cottagesystems.com/jenkins/job/autoplot-test141/ws/diffs.test149_file__home_jbf_public_html_autoplot_data_sav_arrayOfStruct.idlsav_ZZ.XX.png
This is doing something like: set range -> set scale -> set range, and then in the meantime something else is being resized.
For this test it looks like I had the two test results marked as okay were both fails. I've made it so that the primary one is the one which matches what you get when running interactively.