Child project not finding parent with relativePath - maven

Question

I've create a project parent used to manage dependencies and version in child projects, see the pom.xml
<groupId>myCompany</groupId>
<artifactId>parent</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
Than, i created a child project, that inherited from the parent, see the pom.xml
<parent>
<groupId>myCompany</groupId>
<artifactId>parent</artifactId>
<version>1.0-SNAPSHOT</version>
<relativePath>../parent/pom.xml</relativePath>
</parent>
<artifactId>filrstChild</artifactId>
<name>filrst Child</name>
Note the two project are in the same folder
group :
parent
firstChild
PS :
the child projects are already exists before parent, so the architecture is not from scratch, that why i didn't use the standard way to created parent & modules
with gitlab-ci i'm trying to build the firstChild, after building parent
So, parent build correctly, but firstChild is not building
this is my gitlab-ci on firstChild
image: appinair/jdk11-maven
variables:
MAVEN_CLI_OPTS: "-s .m2/settings.xml --batch-mode"
MAVEN_OPTS: "-Dmaven.repo.local=.m2/repository"
cache:
paths:
- target/
build:
stage: build
script:
- mvn $MAVEN_CLI_OPTS clean install -Dmaven.test.skip=true -Dmaven.javadoc.skip=true
artifacts:
paths:
- target/
- .m2/repository/
And this is the error that i got after building firstChild
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.google.inject.internal.cglib.core.$ReflectUtils$1 (file:/usr/share/maven/lib/guice.jar) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain)
WARNING: Please consider reporting this to the maintainers of com.google.inject.internal.cglib.core.$ReflectUtils$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
[INFO] Scanning for projects...
[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[FATAL] Non-resolvable parent POM for myCompany:firstChild:[unknown-version]: Could not find artifact myCompany:parent:pom:1.0-SNAPSHOT and 'parent.relativePath' points at wrong local POM # line 5, column 10
#
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]
[ERROR] The project myCompany:firstChild:[unknown-version] (/builds/compiere-ws/firstChild/pom.xml) has 1 error
[ERROR] Non-resolvable parent POM for myCompany:firstChild:[unknown-version]: Could not find artifact myCompany:parent:pom:1.0-SNAPSHOT and 'parent.relativePath' points at wrong local POM # line 5, column 10 -> [Help 2]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/ProjectBuildingException
[ERROR] [Help 2] http://cwiki.apache.org/confluence/display/MAVEN/UnresolvableModelException
ERROR: Job failed: exit code 1
So, any idea ?
PS:
Note that the firstChild build correctly in my local server or with jenkins, it's not building only with gitlab-ci