apache 2.4 – Proxy to a load balancer automatically add additional path

I’m running httpd 2.4.6 on Redhat 7.9. I’m trying to use ProxyPass work with Balancer. Here is my configuration.

Balancer

<Proxy balancer://mycluster>
    BalancerMember http://10.10.12.103:8080
    BalancerMember http://10.10.12.107:8080
</Proxy>

VirtualHost

<VirtualHost *:8080>

    ServerName      www.abcdef.com
    DocumentRoot "/app/httpd/html"

    <Location /heartbeat >
    </Location>

    <Location /up >
        ProxyPass balancer://mycluster/myapp1
        ProxyPassReverse balancer://mycluster/myapp1
    </Location>
    <Location /myapp1 >
        ProxyPass balancer://mycluster/myapp1
        ProxyPassReverse balancer://mycluster/myapp1
    </Location>
    <Location / >
        ProxyPass balancer://mycluster/myapp1
        ProxyPassReverse balancer://mycluster/myapp1
    </Location>

</VirtualHost>

I was hoping all 3 paths: /, /myapp1, /up can be all passed to /myapp1 on my backend servers. But I got 404 error for /myapp1 and /up.

I checked tomcat access log ad found something was added to the end of the url:

(03/May/2021:22:02:45 +0000)|10.10.55.55|10.29.9.6||-|http-bio-8076-exec-4|0|10.10.55.55|-|-|"-"|"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:32.0) Gecko/20100101 Firefox/32.0"|"GET /myapp1myapp1/ HTTP/1.1"|404|-
(03/May/2021:22:03:01 +0000)|10.10.55.55|10.29.9.6||-|http-bio-8076-exec-5|0|10.10.55.55|-|-|"-"|"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:32.0) Gecko/20100101 Firefox/32.0"|"GET /myapp1up/ HTTP/1.1"|404|-

The url changed: /up to /myapp1up/, /myapp1 to /myapp1myapp1/, obviously not exist.

I tried to research online and didn’t find any result about this. Would someone have experience like this can shed some light why it has this kind of behavior? Thanks