Orlov's perfect-dg-category phantom conjecture

A phantom is a nonzero admissible subcategory whose Grothendieck group vanishes. Let $\mathcal{R}$ be a smooth finite-dimensional dg-algebra, and let $\mathcal{P}\!\mathit{erf}\!\operatorname{--}\mathcal{R}$ denote the dg-category of perfect dg-modules over $\mathcal{R}$. Orlov's conjecture. There are no phantoms of the form

$$\mathcal{P}\!\mathit{erf}\!\operatorname{--}\mathcal{R}.$$

The phantom arising from the non-full maximal-length exceptional collection on the ten-point blow-up of $\mathbb P^2_\mathbb C$ disproves this conjecture.