Zhang et al.'s conjecture on adjacent vertex distinguishing total colourings

Let $G$ be a graph, and let $\chi_{at}(G)$ denote its adjacent vertex distinguishing total chromatic number, the least number of colours in a proper total colouring such that every pair of adjacent vertices has a different set of colours appearing on the vertex and its incident edges. Zhang et al.'s conjecture. For every graph $G$,

$$\chi_{at}(G)\leq \Delta(G)+3.$$

The conjecture seeks a sharp general upper bound for adjacent vertex distinguishing total colourings. The source gives no resolution, so the conjecture remains open.