The LTYPESHP.SHX that comes with AutoCAD is a shape file, not a text font file. If you load a drawing where a text style incorrectly uses LTYPESHP.SHX, then from that point on until you exit out and restart AutoCAD, in every drawing you open, AutoCAD will not read LTYPESHP.SHX correctly. For example, I open this drawing called WKS_COPY.DWG and as it loads I get an error message reading
ltypeshp.shx is a shape file, not a text font file.
Now I open a second drawing called BR.DWG, where there are complex linetypes that use the shapes defined in LTYPESHP.SHX. One of them is a linetype for a fence line that ordinarily shows a line with little circles in it, like this: ----O-----O-----O---- where the little circles are shapes. But since I had opened that other drawing first which incorrectly tried to use LTYPESHP.SHX as a text font, in the second drawing BR.DWG, those linetypes are displayed without the circles: ----- ------ ------ ---- . The only way I have figured out to make those linetypes display properly in BR.DWG is to exit out and restart AutoCAD, and open BR.DWG first before I open WKS_COPY.DWG. I see this behavior in AutoCAD 2007 and AutoCAD 2016.