When using a constraints object with maxZoom of 15, snapToZoom true (default), and a minZoom of 6, clicking the "+" icon in the zoom widget pops the zoom level back several levels. (NOTE: you must wait for map to stop moving at level 14 before clicking the "+" icon).
See this codepen for example: https://codepen.io/anon/pen/MzxKbd
1. Is this an arcGIS JS 4.9 bug? If so, might it be fixed in the upcoming 4.10 release?
2. Is there a workaround for this issue besides setting snapToZoom to false? In my current application we are doing this, but it seems to be leading to other problems; for example, making it possible to zoom in beyond the max zoom level. We also cannot change the minZoom and maxZoom levels.