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The current situation with the recently discovered $a_0(1700/1800)$ resonanceis very paradoxical: it is believed that $a_0(1700/1800)$ must be stronglycoupled with two vector mesons, but there is no direct experimentalconfirmation of this yet. Based on the assumption that the $a_0(1700/1800)$ isa state similar to the four-quark state from the MIT bag, belonging to eitherthe $\underline{9}^*$ or the $\underline{36}^*$ $q^2\bar q^2$ multiplet, weanalyze the influence of the strong $a_0(1700/1800)$ coupling to the vectorchannels $K^* \bar K^*$, $\rho\phi$, and $\rho \omega$ on its line shape in thedecay channels into pseudoscalar mesons $K\bar K$, $\pi\eta$, and $\pi\eta'$.This effect depends on the location of the resonance mass $m_{a_0}$ relative tothe nominal thresholds of vector channels. For example, if $m_{a_0}\approx1700$ MeV, then the influence turns out to be hidden in a fairly wide range ofcoupling constants. On the whole, our analysis shows that, to confirm thepresence of the strong $a_0(1700/1800)$ coupling to the vector channels,utterly required is the direct detection of the decays $a_0(1700/1800)\toK^*\bar K^*$, $\rho\phi$, $\rho\omega$. The appearance of even certain hints atthe existence of these decays would make it possible to fundamentally advancein understanding the nature of the new $a_0$ state.

Coupled-channel influence on the $a_0(1700/1800)$ line shape