Why are the LED displays on the plugin not appearing?
If your plugin is displaying similiarly to the EchoBoy instance below, then you may have upgraded your macOS version recently.
Figure 1: EchoBoy with the Mojave graphics bug
This issue occurs with Soundtoys 5.2.4 or earlier on macOS 10.14 or newer. This was fixed in Soundtoys 5.3.0, so you just need to download and install the latest version of Soundtoys available. You can find this in your Soundtoys account if you've set it up, or in your email under your order confirmation.
NOTE: This also occurs Soundtoys 4 and earlier versions, but there is no fix other than upgrading to Soundtoys 5. macOS Mojave is not compatible with those versions, so refrain from upgrading if you need to continue using Soundtoys 4 or prepare to upgrade your Soundtoys license as well.