I discovered this whilst writing the MATE section for the Date & Time page in the Solus Help Center and Josh has requested I file it here. This is a freshly installed copy of Solus MATE in a virtual machine.
Steps to reproduce -
Brisk Menu > Administration > Time and Date > changing the Configuration from "Manual" to "Keep synchronized with Internet servers".
Result - A message asking to install and activate NTP support, as shown in screenshot below.