Unfortunately for you, the "updates" would be to upgrade to the latest release of FileMaker 12--12.0v5. As far as I know FileMaker will not be releasing any bug fixes for older versions of their product line.
But what you describe doesn't match any current reports of trouble with FileMaker 11 and Mavericks that I can recall. Please try the following tests to rule out other possible issues.
Create a brand new simple test file with just one or two fields and test it to see if you get the same behavior.
Trying changing the font specified for you field and see if that makes any difference.
Hi! Thanks for your input PhilModJunk
OK I tried changing the font from our corporate one to Arial. That doesn't work.
How do I create a brand new simple test file with just one or two fields?
Do you mean try typing a new estimate within the existing estimate database.. or create a completely new document format? I'm not sure how to do this!
I mean select New Database from the File menu. Name the new file. Define a field or two and see if it shows the same behavior. The idea here is to test a shiny brand new file that can't possibly "inherit" any file corruption from an existing file so as to rule out the possibility that your file or layout is damaged.