Some bug in my code added descriptor blobs which had gone through the following transformations:

np_blob = a 64 dim np float32 array
blob = np.frombuffer(np_blob.tobytes()).tobytes()

After this blob becomes a 32 dim np.float array.

Issue 1 - AddDescriptor for a 64 dim set worked fine with this blob
Issue 2 - A FindDescriptor query with k_neighbors crashes the server:
Server log

vdms: src/property.cc:44: PMGD::Property::Property(const PMGD::Property&): Assertion `0' failed.