Quick Thoughts changed the decimal point in balance, now I have $50 more? Is this too good to be true? What should I do?

Opened Quick Thoughts app with a $5.30 balance. Tried a $1 survey and was disqualified, the balance should be $5.40.
But when the screen refreshed for new surveys, it became $54.10!!

Looked at transaction summary and don't see $50 credit.

Has this happened to anyone before? What should I do? Or just keep the money?