Clean well the area of arcing, and see with a magnifier if there are crackings in the wire.
Search the datasheet of fbt to known if the wire is replaceable. As the crack must be near the fbt, if the wire is replaceable, and can be removed you could cut a bit of wire to avoid the damaged part and reinstall the wire, normally is long enough. But you must first be sure that the HV wire is removable, and how. In some fbt it is removeable, in others not.
And you must consider how the wire has been damaged. Have you forced? Is too old and the plastic is degraded?
In the past there was a product specially designed to cover cracks in fbts (when all tvs have one), but I don't remember the name, and surely now is not manufactured.
I don't think that is related with the capacitors, unless you have bent too much or pinched the wire while changing capacitors.
Not very related, but if you change some capacitors in the H deflection circuit, you can raise too much the HV, and increase the X ray emission. I think that in this case the picture is abnormal, too much narrow or wide, not your case, but it is another reason to not play with this circuit.