Thank you for the post.
I am able to replicate this on iOS 6.1.3 when using FileMaker Go 12.0.7. The previous release version FileMaker Go 12.0.6 does not appear to be affected.
I forwarded a full report to Testing and Development for review.
Actually, this problem was also present in Go 12.0.6. But I never got around to reporting it. When the new version came out, I waited until I had a chance to test it.
It seemed to me that in the 12.0.6 version, the glass went blank on the firts or second character -- now the first three characters are affected. I think something has changed between the two versions. Perhaps a diff of the source trees might reveal something if it isn't obvious.
I have an iPad 1 and my customer has an iPad 4, both with iOS 6.1.3 and FMGo 12.0.7. We have experienced the same issues on our custom solution and are keen to have this resolved - it is extremely inconvenient.