Odd cursor behaviour in text entry fields

This is driving me a bit mad.  I have two text entry fields on a software sim within a scrollable panel.

One field, the user can type in it, come out of it, click back into it and the cursor will go exactly where the mouse clicks, which is exactly as a user would expect.  You can also use the mouse to highlight all/part of the text and delete.

The second field, once you've typed something, come out of the field, and then try to go back into the text field, the cursor will ONLY sit at the end of the typed entry.  So you can't change one character, or start at the beginning and hit the delete key, or highlight part of the text and delete it.  This doesn't behave as expected.  

Most users still ought to be able to figure it out, but because it doesn't behave as expected I could see it causing confusion with some of our users. 

(the 25, below is a text field, as is the 12.30).  The one with 25 works perfectly, the 12.30 one does not.  I think it may have something to do with the scroll panel as adding in new text fields into the page seem to work as expected, but the minute I drag one into the scroll panel, it misbehaves.  However, when I created a new test file with a scroll panel with two text fields, they both behaved just fine.