Hey. I am glad that all models arrived safely!
The blue bar and the letters "MС" mean that this combat vehicle belongs to the peacekeeping forces (Миротворческие силы). Specifically, this variant of the coloring of the BMP was used in the Russian peacekeeping contingent in Abkhazia in 1994.
If this type of coloring does not suit you, you can paint over these stripes. It may even be clearly visible, but this is quite acceptable in reality, when the BMP was withdrawn from the peacekeeping contingent and has not yet undergone a scheduled repair and updating of repainting.