Hey mibtp,
I was running into the same annoying problem, and this fix worked for me…
Try changing the error message style to the floating-tip type. Here’s a page with the instructions:
http://contactform7.com/customizing-validation-error-messages/
the default style is ‘static’, but changing this style will remove the error message upon hover of the text field. All I did was add this code:
html_class=”use-floating-validation-tip”
to the line where the contact form is added on the page in the admin panel, and it fixed it right up for me.
Hope it works for you too!