If some errors occur during "compile-common-jsp" target in portal-web/build.xml, the build can still show as Successful.
org.apache.jasper.JspC is run in a forked jvm without a failonerror. The target will check the output and fail for "JasperException", but not any other exception.
LPS-85089, this target will run by default (jsp.precompile=on)
Failure in 6.2 (LPS-87504) was largely undetected or ignored for months.