Bug - iOS Shaded Relief (ESRI) Display

I'm seeing what appear to be bugs in layered maps display on iOS (iPhone 7) with the Shaded Relief (ESRI) layer:

• I have Gaia Topo (feet) as the base layer, Shaded Relief (the ESRI one) at 100% as the second layer, everything else removed for now.
• After setting everything up, if I adjust the opacity on the Shaded Relief layer to 100%, things display pretty well.
• While zooming in, somewhere in the 1/4 mi grid zoom level, the Shaded Relief layer disappears completely.  If I zoom back out, it reappears.
• If I go to the iOS Home Screen (not even a hard close for Gaia) and then reopen Gaia, the Shaded Relief layer disappears, independent of zoom level.  Zooming won't bring it back - I have to adjust the layer opacity to get it to reappear.
• If I add another layer (i.e. the new "Slope Angle - Avalanche" layer), the Shaded Relief layer disappears until I adjust opacity on it.  If I adjust opacity on another layer, the Shaded Relief layer disappears again until I adjust opacity on it.

The "Shaded Relief (US)" one from CalTopo doesn't have this strange behavior, but unfortunately the CalTopo one is missing data for some areas of Alaska.  Also, the ESRI one seems to have been based on a higher-resolution digital elevation model.

Note that I see totally different Shaded Relief layer behavior on the web site.  The iOS behavior, albeit buggy, is still better.  On iOS, at 100% opacity, the Shaded Relief layer appears to behave like an alpha layer that lets the underlying map bleed through, especially in areas where Shaded Relief is white.  On the web site under Chrome, the Shaded Relief layer at 100% opacity completely blocks the underlying layers.  Because the Shaded Relief layer from ESRI is much lighter than the one from CalTopo, it's almost useless on the web site under Chrome - if it's opaque enough to be visible, it's opaque enough to block the underlying map.