Kontsevich's proper DG algebra degeneration conjecture

Let $B$ be a proper DG algebra over a field $cmathrm k$. The Hochschild homology pairing is a map $HH_{\bullet}(B)\otimes HH_{\bullet}(B^{op})\to \mathrm k$, and let $\delta:HC_{\bullet}(B^{op})\to HH_{\bullet}(B^{op})[-1]$ be the connecting map. Kontsevich's proper degeneration conjecture. The composition map

$$(HH_{\bullet}(B)\otimes HC_{\bullet}(B^{op}))[1]\xrightarrow{\operatorname{id}\otimes\delta}HH_{\bullet}(B)\otimes HH_{\bullet}(B^{op})\to\mathrm k$$

is zero. This is a proposed extension of Hodge-to-de Rham degeneration from smooth and proper DG algebras to proper DG algebras; the paper disproves it by constructing a counterexample.