Running ionic ipa created --prod flag

We have ionic cordova based hybrid application. When we create an ipa with the below command
ionic cordova build ios --prod .

We see sometimes blank screen in the application during test case run using appium.
Also during manual test of the same ipa we do not see those issue as in case of appium run (blank screens)

But when we build the same ipa without prod flag we do not see this issue.

Can anyone suggest what could be reason for this?