Diagnose Android Game Bug

I need a fresh pair of eyes on my Android game, Math Tug of War (Google Play link: https://play.google.com/store/apps/details?id=com.oubacode.arqon). There is a stubborn issue hiding somewhere in the gameplay loop and I have not been able to pin it down.

Here is what I expect from you:
• Install the current production build on an Android device.
• Play through the full gameplay mechanics—every level, power-up, win / loss scenario, and in-game reward—until the fault appears.
• Capture logs, screen recordings or crash traces that prove exactly where and why the problem occurs.
• Explain, in plain language, the root cause and outline the fix. If you can include a concise technical snippet or configuration change, even better.

Feel free to note anything else you notice in the UI or performance, but the winning deliverable is the reproducible cause of the gameplay bug. First person to hand me a clear, verifiable explanation earns the €1 000 payment.

Send your findings, supporting evidence, and suggested remedy when ready; I will test it immediately and release payment once the issue is confirmed and the fix path is clear.