hammer lacquer clumping

[Greg Graham]

I have some lacquer for hammer voicing (from Steinway)
which, after dilution, forms a clump in the bottle,
looking something like a Lava Lamp.  I'm using
standard "Lacquer Thinner".  

If I shake the bottle for a loooong time, the clump
gets smaller, but never really goes away.  

I've never experienced lacquer that wouldn't stay
dissolved.  What's up?

Greg Graham
Brodheadsville, PA