Hi,
If you're using parcels, then you're seeing this because the parcel style is controlling the parcel segment linetypes. The segments or linework which is not part of a parcel would be displaying the linetypes associated with whichever layer it resides on.
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Just to add on to what schroederC3D said:
If the lines are parcel segment lines and they're parcels of different styles sharing those segments, the SITE has a setting for controlling the order in which styles are applied to the segments in shared situations. And, the site itself has a parcel style.
I have a situation with my linetypes. every so often the linetype scale changes on the linetype. I have to re-load the linetype. Is there a fix or a setting for this?