Lightroom Mobile: Smart Previews with transparency show gray instead of white until sent to Edit and back

Rikk: All latest versions of iOS and LR.

As I mentioned in another thread, one workaround for now is to add a solid white layer below the transparent layer in PS. Then if already synced with LR, read the new metadata from the file. Then when the file syncs to mobile the transparency will not show as grey.

LR Mobile / IOS displays transparent pixels as grey rather than white (at least sometimes).

Here's a simple test PNG with some pixels transparent: 
https://www.dropbox.com/s/aah9axe1axoykxv/transparent-2019-06-20.png?dl=0

That image appears in LR Classic and LR Desktop as all white, because they display transparent pixels as white.  But after LR Mobile / IOS yncs from LR Classic, the transparent pixels initially appear as grey:



But then switching back to grid view and then full image view a couple of times, the transparent pixels turn all white.  

I observe that same behavior using John Weber's original test PSD: 
https://www.dropbox.com/s/xfjf3eq4t92djld/AMI-19d6_289-Test.psd?dl=0

Tested on LR Mobile 4.3.1 / IOS 12.1.4 and LR Classic 8.3.1 / Mac OS 10.14.5.

John

Is the device iOS or Android?
Lightroom Mobile Version number?
OS Version number?