Chain sagging on right chain stay

[lspeedguy]

I've got Ultegra RD-8000 rear derailleur,two chain rings, and 11 cog rear cluster - when I shift into the small chain ring and the 5th smallest cog, the chain sags over the right chain stay - if I rule out an overly long chain, what else could cause this to happen.

The bike was in the shop recently and the mechanic did make a few adjustments with respect to the rear mech.

Thanks in advance for any thoughts/insights.

 

[dabac]

Your freehub may not be coasting quite as freely as it should. A flush and lube may be in order.