Reproduction steps:
1. Open the attached user's project "1019086-Poker.zip"
2. Enter Play Mode and observe the poker chip count
3. Run a Mac build with the Graphics API value set to OpenGL Core on a Mac with an integrated graphics card.
4. Observe the poker chip count

Expected results: all poker chips show as in the Editor
Actual results: bottom layer of chips (using single buffer for both UV and alpha properties) is invisible due to Alpha remaining at the default value (see attached Results.png)

Reproduces on: 2019.4.26f1, 2020.3.9f1, 2021.1.8f1, 2021.2.0a17
Could not test on 2018.4.35f1 due to the project breaking when downgrading

Reproducible with these machines/browsers:
iMac (21.5-inch, Late 2013), OSX 10.14.6, i5-4570R @ 2.7GHz, Intel Iris Pro 1536 MB
MacBook Air (13-inch, mid 2012), OSX 10.14.6, Chrome 90.0.4430.93, Firefox 88.0
MacBook Air (13-inch, mid 2012), OSX 10.15.7, Chrome 89.0.4389.114
MacBook Pro (Retina, 13-inch, Early 2015), OSX 10.14.5, Chrome 89.0.4389.82
MacBook Air (13-inch, Early 2015), OSX 10.15.7, Chrome 87.0.4280.141

Not reproducible with these machines/browsers:
Windows 10 (Microsoft Edge, Chrome and Firefox)
MacBook Pro (Retina, 15-inch, Mid 2014), OSX 10.15.4 (Safari and Chrome)
MacBook Pro (15-inch, 2016), OSX 10.15.7 (Chrome version 90.0.4430.93, Firefox version 87.0, Safari version 14.1)
MacBook Pro (15-inch, 2019), OSX 10.14.16, Chrome 89.0.4389.114
MacBook Pro (16-inch, 2019), OSX 10.15.7, i9 2.4 GHz, Intel Graphics 630 1536 MB