no proper shutdown of spring boot app on a linux tomcat service

I have following envirnonment Spring boot (3.1.1) web app, running on tomcat 10.x as a systemd service, on RHEL9. It uses a ehcache, configured to be persistent across restarts. If I start & stop tomcat manually per ./startup and ./shutdown, I can see a

DEBUG o.e.c.EhcacheManager - Close successful.

in my log. That means, the cache is closed properly, and the cache is still valid after restart. On starting & stopping tomcat per service I miss that log entry, and indeed the caches are not properly closed and renewed after restart.

[Service]
...
ExecStart=/opt/xxx/apache-tomcat/bin/catalina.sh run
ExecStop=/opt/xxx/apache-tomcat/bin/shutdown.sh

These are the same scripts I run manually. Something I am not understanding is happening in this shutdown phase. Is the service stop running into a timeout and than forcing a ungracefull tomcat stop? ###### Actions taken: Log level for EHCachemanger set started/stopped manually and per service