Diagonal lens flare with street lights

[Skaperen]

A diagonal spike like in the OPs photo is likely not caused by the aperture blades.

These look a LOT more like streaks due to incomplete cleaning. The streaks are from grooves at 90 degree angle in the fine oil or water surface on the lens. It can be from finger oil contaminating the cleaning cloth itself. Condensation of water onto that can then make it worse. Get a NEW microfiber or chamois cleaning cloth and avoid applying any surface of the cloth which has been touched to the lens (or filter if that was on when shooting).

Also, if you remove the filter to shoot (it helps because there is less dirt and reflective/refractive surface for the light to be disturbed by), be sure to put the filter back on afterwards to keep the lens protected from damage or dirt/dust.