Incorrect colors on graphs from slave nodes

I have set up two test nodes: Master and Slave. On both nodes frontend theme is Black&Blue.
In the frontend of Master node graphs for hosts on Master node are shown with correct (dark) colors.
In the frontend of Slave node graphs for hosts on Slave node are shown with correct (dark) colors.
In the frontend of Master node graphs for hosts on Slave node are shown with WRONG (light) colors.