Malware in Ulefone Calculator App?

Hello,

I have an Ulefone 7 and AVG Antivirus running on it. Yesterday, I updated the Virus Definitions after 3 weeks and did a scan. A malware was reported in the pre-installed Calculator App. Is this a false positive? The app has been on the phone since I bought it new ~3 years ago and never before AVG detected anything. No updates of the app I believe in the recent past. I installed Kaspersky, which also reported a Maleware detection in the prizeCalculator.apk in the /system/priv-app folder. No detections were reported by Avira and Malewarebytes. I also found this Sophos-Discussion from 3 years ago where the same problem was reported but not solved: https://community.sophos.com/sophos-mobile/f/discussions/122870/ulefone-malware-detected-in-pre-installed-calculator-app. 

I deactivated the app for now. More things I need to do?

Has anyone had the same experience?