There are some default limits to the side by side comparison.
In local.properties for the installation where this Workstation is running, increase the default limits by adding the following:
lisa.graphical.xml.diff.engine.max.differences=10000
lisa.graphical.xml.diff.report.max.linewidth=2000
lisa.graphical.xml.diff.report.max.numberoflines=1000
These values are just an example and may need further increasing if the result is still truncated.
<Please see attached file for image>

For further details regarding these properties see:
https://docops.ca.com/devtest-solutions/10-3/en/using/using-ca-application-test/using-devtest-workstation-with-ca-application-test/running-test-cases-and-suites/interactive-test-run-itr-utility/graphical-text-diff-utility