I dont mean to be nitpicking but after I noticed this, I somehow cant seem to unnotice it.
The seraphim decal/tarmac for small structures has this dirt like box outline when viewed in closer zoom with textures like snow. Other factions are clean.
I found the .dds files for the tarmac within the env file (main FA installation). The original developers didnt clean up the edges of the alpha channel.
In anycase I erased the patches using photoshop and nvidia dds plugin and placed them in the zip file for reference.
This is just a minor cosmetic issue but it would be great if a fix could be included in future FAF versions.