This is not a bug; all resources are capped at 2k capacity. If you want to store more resources near your core, use vaults.
When will this update come to Android phones?
Every build of 4.0 has been available for Android as an APK file download here on itch.io.
If you're asking about the Google Play store, it'll be released to production once it's no longer in alpha/beta.
Thank you for the explanation! This version (4.0 Alpha v54) is much better than the 3.5 one, it just lacks a tutorial or explanations, but I managed to learn about every block and how it works through trial and error. Great game.