Matsui 1410r horizontal menu lines flicker/jump

[HighHat]

 Hello everyone, I haven't looked at a crt in a long time and was surprised when I seen the menu boxes jump up and down rapidly, I don't ever remember this before. Is it normal? It's quite nauseating and happens on every menu.. (tv,dvd and freeview menu) the tv is clocked at 50hz PAL. Does anyone know what would cause this?