Sometimes the textfield is not clickable, i.e. when you roll over the cursor changes to the link cursor and you cannot use any of the links in the text. Then if I refresh it works fine and I can access the links.
Do you have any other masks / plugins / that might be "over" the textfield... even if not visible?
If the zorder is not set... then it's possible that sometimes the textfield is on top... and sometimes it's not... but this only has been an issue if there are overlapping elements.