I have a MapServer accessed via MapImageLayer that has some raster & vector sublayers. the vector layers can all be queried or identified just fine but none of the raster sub layers work. the same raster data published as ImageServer also works fine.
debugging i see a bare bones 400 error, something's missing (no details) from querying the raster layers. the REST calls were captured & modified to use on the vector subayers, again these worked fine.
i assume this actually works (googling doesn't find similar issues) & the problem is the data publishing.
ags: 10.31 & 10.41
js api: 4.8