Hi there,
It looks like you are using blind or buried vias in your design. Not all vias in your design connect the same layers. Because of this, Ultiboard is exporting a seperate drawing for every layer to layer via combination that you are using in your design. There are 3 of these combinations in your design and Ultiboard is exporting 3 drawings. All 3 drawings are exported in one drill symbol file.
Most gerber viewers don't support the LN command (layer name) which is used to indicate multiple drawings in one gerber file. Hence, it appears to the user that there is overlapping or incorrect text. This is what your board house may be seeing. However, the built in gerber viewer in Ultiboard handles this command correctly. Simply, open the gerber file in Ultiboard. You may have to change the colour of the imported layers to be visible. You can set the visibility of each of these drawings by setting the check boxes in the Layers list.
In short, what you are seeing is correct behaviour. Just make sure that you are using a gerber viewer that supports multi-layer files.
Hope that helps.
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Yi
Software Developer
National Instruments - Electronics Workbench Group