I have seen this happen(or not happen) several times in the past. You are in a drawing that has xrefs attached AND the xref layers have been modified(color and/or linetype) within this drawing. You then make changes to the xref drawing(add or delete layers, change color and or linetypes, etc). When you open the other drawing again, the new changes will not display.
The only way to get it to display is to detach the xref, purge then re-attach the xref, then fix all the layer changes you had associated with that sheet.
Is there a way to force the xref changes in the sheet?
The only real control over that is VISRETAIN. You can only set it to 0 or 1, though, so it's an all-or-nothing sort of thing.