"GLSL compilation failed" exceptions are thrown on switching Windows Graphics APIs to OpenGLES2.

Steps to repro:
1. Create a new Project.
2. File > Build Settings > Player Settings.
3. Other Settings > Uncheck "Auto-Graphics API for Window" checkbox.
4. Add OpenGLES2 > move to the top of the list > Apply.

Actual Result:
GLSL compilation failed exceptions are thrown in the console.

Expected Result:
No error is thrown in console.

Reproducible in:
2019.1.0a13, 2019.1.0a12, 2019.1.0a11, 6c78e70340ba, 2019.2.0a1 (9528a0cc545d)

Working Fine in:
2019.1.0a10, 2018.3.0f2 (49866f0a5d12), 2019.2.0a2 (fd05123cf2d2), 2019.2.0a3 (35393104434b), changeset: 407898:cd7a61452589, changeset 406498:f85b6630fed1

Other error: 407944:726ceabcc068
"0(58) : error C7548: '&' requires "#extension GL_EXT_gpu_shader4 : enable" before use"
That error is absent (maybe fixed?) from 2019.2.0a2 (fd05123cf2d2) which is more recent, but comes back with a vengeance with 2019.2.0a5 (726ceabcc068) and posterior --> so we probably have two unrelated bugs overlapping each other.

Environment:
Occurs only on Windows.

Stack trace:
GLSL compilation failed:0(31) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"0(34) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"0(37) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"0(40) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"0(43) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"0(46) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"0(49) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"0(52) : error C0000: syntax error, unexpected integer constant, expecting "::" at token "<int-const>"

Additional notes:
The bug also happens if you open the project while already using OpenGLES2.
And the same bug happens with same error with OpenGLES3.