Order of light calculation on scene

Question

Does lights (or their type) order on scene matters?

I'm working on forward renderer using OpenGL and I have different results (shadow color) depending on lights order (each light got it's own pass with additive blending)

Answer 1

I used wrong order of configuring rendering pipeline:

bind framebuffer
set viewport & clear buffers
depth stage settings
blending settings
other rasterizer settings

I've moved set viewport & clear buffers to the end. Now everything looks the same regardless of the lighting (render pass) order.