I see a weird error

It says: ERROR: System.FormatException

My project is blueprint-only project. I am trying to package development version of IOS but System Format Exception has occurred.

Hello,

We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.

https://forums.unrealengine.com/unreal-engine/announcements-and-releases/1410408-unreal-engine-bug-submission-form

Thanks