Template overriding when new package installed

We have new package which has new group id and artifact id in pom.xml

So when we install this new package the aem template structure is reverting the template changes and structure as well.

This happens only when we uninstall old version package and install new. And we dont get back the templates.

Is this because of group id change? The new version uninstalls old version and then installs new version? Or due to resource resolution conflicts.

This happens only 1time! Will it reoccur?