Grails 5 application is not finding GSP files in .war, grails run-app is fine - grails

Question

I have an application that runs perfectly using grails run-app but fails when I try to run is using the embedded server. I use the following commands to build and run the .war.
./gradlew assemble
java -Dgrails.env=dev -jar build/libs/rideshare-services-3.0.war
Below is the error and the steps I've taken to try to determine what the issue is.
The browser shows 500 error page, and the log shows the following:
Servlet.service() for servlet [grailsDispatcherServlet] in context with path [] threw exception [Could not resolve view with name '/index' in servlet with name 'grailsDispatcherServlet'] with root cause
javax.servlet.ServletException: Could not resolve view with name '/index' in servlet with name 'grailsDispatcherServlet'
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1384)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1149)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1088)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
<snip>
However, spring security is enabled, and it renders its form fine with this path:
/login/auth
So I started poking around and assets can be accessed, for example:
/assets/advancedgrails.svg
Also, the built-in actuator paths all work fine:
/actuator/*
I found this question
grails and debugging UrlMappings which seemed like it could help.
To test if the URL mapping were working I added a /test route in UrlMappings.groovy, mapped to a controller named 'member' and the 'index' action.
I also added the logging as suggested:
<logger name="org.grails.web.mapping" level="ALL"/>
It resolved to the correct controller and action, but still failed to load the page, so I added a log statement to the action, and the controller definitely runs, but the view fails to load.
At which point, with the debug statement in the controller, I could confirm that even without the /test URL mapping, the controller fires if I use the standard controller/action URI /member/index. That confirmed that the configuration in UrlMapping.groovy was working.
So, thinking the .gsp files failed to be compiled, I searched and found this:
Grails 3 application works locally, but unable to resolve view when deployed to a remote Tomcat
But I already had the plugins suggested in the answer in my build, so I figured maybe they weren't be added to the .war so I unziped it.
The .war has the gsp files as well as a mapping file WEB-INF/classes/views.properties which included a mapping for the view that corresponds to the controller/action I was using to test (among all of the other mappings in the file):
/WEB-INF/grails-app/views/member/index.gsp=gsp_rideshare_services_memberindex_gsp
I then confirmed the referenced gsp_rideshare_services_memberindex_gsp files exist, and the do with the following being present WEB-INF/classes:
gsp_rideshare_services_memberindex_gsp_html.data
gsp_rideshare_services_memberindex_gsp_linenumbers.data
gsp_rideshare_services_memberindex_gsp.class
gsp_rideshare_services_memberindex_gsp$_run_closure1.class
gsp_rideshare_services_memberindex_gsp$_run_closure1$_closure3.class
gsp_rideshare_services_memberindex_gsp$_run_closure1$_closure3$_closure4.class
gsp_rideshare_services_memberindex_gsp$_run_closure2.class
gsp_rideshare_services_memberindex_gsp$_run_closure2$_closure5.class
gsp_rideshare_services_memberindex_gsp$_run_closure2$_closure6.class
gsp_rideshare_services_memberindex_gsp$_run_closure2$_closure7.class
The compiled .gsp files for all of my views seem to be here, and the source .gsp files are also in WEB-INF/classes, in the same folder structure as the project's grails-app/views directory.
So at this point I'm at a loss to understand why my views (gsp files) are not being found, although built-in views and plugin views are fine.
I will reiterate that the app runs perfectly well when run using 'grails run-app'.