After image validation error the upload field becomes 'required'

Hi,
i don't if this is a bug or not but here's the problem:

I have a flexinode image field, which works brilliantly when the image specifications are met. ie. it's the right width, height and filesize.

If the specifications are NOT met it correctly flags it up and produces the correct 'error' message.
ie. The uploaded image is too large; the maximum dimensions are 100x100 pixels.

BUT this now makes the image field become a required field and the error message will not go away even though the image field is not a required one.
To get rid of the 'error' message i have to log out and log back in again, so i guess the error message session is not being destroy!!

has anyone else experienced this or anyone got any suggestions to overcome it???

thanks everyone

Tom