Autodesk Maya 2018.5 [verified] -

might go missing or lose color after updating from previous versions. Installation

: Includes updates to the Maya API to improve plug-in development efficiency and minimize disruptions for developers. Autodesk Maya 2018.5

Between 2016 and 2020, Viewport 2.0 went through growing pains. Maya 2018.5 represents the "Goldilocks" zone: might go missing or lose color after updating