Whenever I am in Adobe Reader in OSX, two odd behaviors become apparent. First, whenever I scroll up using the arrow keys, closely spaced horizontal lines appear, which disappear whenever the document is zoomed. Second, whenever I am typing data into a form in a PDF, the text I enter does not appear until I click out of that particular form. I am using the latest version of reader, 9.4.0
What version of OS X? Does it happen with all forms or just a few forms. Are the forms you are having problem with Acrobat based forms or a LiveCycle Designer forms?
Acrobat based forms.