I can confirm your issue, when build in the cloud. Probably related to the new hybrid release, see: https://docs.mendix.com/releasenotes/hybridapp/
Can you submit ticket to Mendix support?
A workaround is to build the app yourself, and then update the config.xml, and remove the default splash screen element i.e.
<!-- <splash src="splash.png" /> -->
Let me know if this works for you?
Hi everyone, the issue was fixed. The automated build came back to work properly.