There is a chandelier for four lamps - three in a circle and one in the center.

6-watt LED lamps are screwed into three plinths and a 10-watt lamp is screwed in the center. All lamps produced by OSRAM if that.

When you turn on the chandelier, the Central lamp shines and does not Shine. Lives his life shorter.
The problem is not exactly in the lamp because I tried to change the lamps on identical chandeliers.

Tell me what the problem is?