@ignstein – I've already seen some issues both with IDML writing and IDML interpreting.
If an IDML file is opened by InDesign all page items are created from scratch, text will be recomposed, "small things" like character styles with preserved kerning (possible with InDesign CS3 and CS4, no more with CS5 and above) will lose their kerning even when opened in the same version the IDML file was built from, but not if you open the CS4 file in CS5 (or above)… *
So, yes. Possible that your numbered lists will not work as before.
What exact InDesign version on what OS are you on?
Version of InDesign that exported the IDML?
Version of InDesign that opened the IDML?
* For a detailed description of that particular issue see the German InDesign Forum at: