Deployment project's versioning is showing and creating inconsistent results

Deployment project's versioning not showing the correct value or inconsistent. Versioning format:

${bamboo.version}.${bamboo.buildNumber}

Version is a custom variable added in plan config and buildNumber is system variable.

Check the following screenshots for the behavior.
Versioning preview for the current/latest build. The same behavior on clicking Create Release from any possible build:

Versioning preview when selecting other build from the list. The preview won't change anymore:

Final results are affected as well. The versions are inconsistent. The variable bamboo.version will increment correctly if nothing touched during the release. If the preview has been changed as in the second screenshot, bamboo.version won't have an increment. Following release with untouched versioning will suddenly jump to a number where bamboo.version should have been incremented.