  JKCS041 ($z=1.8$) is one of the most distant galaxy cluster systems known,
seen when the Universe was less than 4 billion years old. Recent
Sunyaev-Zeldovich (SZ) observations show a temperature decrement that is less
than expected based on mass estimates of the system from X-ray, weak
gravitational lensing and galaxy richness measurements. In this paper we seek
to explain the observables - in particular the low SZ decrement and single SZ
peak, the projected offset between the X-ray and SZ peaks of $\approx$220 kpc,
the gas mass measurements and the lensing mass estimate. We use the GAMER-2
hydrodynamic code to carry out idealized numerical simulations of cluster
mergers and compare resulting synthetic maps with the observational data. The
observations are not well reproduced by an isolated cluster, while instead they
are when considering cluster mergers viewed a few tenths of a Gyr after first
core passage. A range of merger scenarios is consistent with the observations,
but parts of parameter space can be ruled out, and generically some kind of
merger process is necessary to reproduce the offset between the SZ and X-ray
peaks. In particular, a total mass of $\approx$2$\times 10^{14} M_\odot$, mass
ratio of $\approx$2:3, gas fraction of $0.05-0.1$ and Navarro, Frenk and White
(NFW) mass density profile concentration $c$$\approx$5 for both components are
scenarios that are consistent with the observational data.
