Thank you for your post.
Our Development and Testing departments are aware of this issue under IOS. This occurs for all versions of FileMaker Go 13. I have attached your post to the original report. When more information becomes available, I will post again.
An entry in the Known Bugs List has been linked to this Issue Report. Any Comments/Questions/Suggested Corrections should be posted here or in a new thread. Please do not post such comments to the Known Bugs List thread.