a total guess with out time to research ..

Is there an option to have the 218 volume set to full? If so please test.

Main: G61SL, 218, HD621, 2*7200SE, 7200HCSE, M6s, DSW, Apple TV 4K, NUC (Roon server)
Secondary: Wiim Pro, 3200, Audio Core 200
F80