  We present optical spectroscopy obtained with the GTC, VLT and SALT
telescopes during the decline of the 2016-2017 outburst of the black hole
candidate GRS 1716-249 (Nova Oph 1993). Our 18-epoch data set spans 6 months
and reveals that the observational properties of the main emission lines are
very variable, even on time scales of a few hours. Several epochs are
characterised by P-Cyg (as well as flat-top and asymmetric) profiles in the
H$\alpha$, H$\beta$ and He II ($\lambda$4686) emission lines, implying the
presence of an accretion disc wind, which is likely hot and dense. The wind's
terminal velocity ($\sim$2000 km s$^{-1}$) is similar to that observed in other
black hole X-ray transients. These lines also show transient and sharp
red-shifted absorptions, taking the form of inverted P-Cyg profiles. We argue
that these profiles can be explained by the presence of infalling material at
$\sim$1300 km s$^{-1}$. We propose a failed wind scenario to explain this
inflow and discuss other alternatives, such as obscuration produced by an
accretion-related structure (e.g. the gas stream) in a high inclination system.
