Shader error is shown when using a custom shader

Reproduction steps:
1. Open the attached “IN-14498” project
2. Observe Console Window logs

Expected result: No shader error is shown in Console Window
Actual result: Shader error is shown in Console Window

Reproducible with: 2020.3.38f1, 2021.3.9f1, 2022.1.15f1, 2022.2.0b7, 2023.1.0a10

Reproducible on: Windows 10 Pro 21H2

Note: Shader error in 'NewSurfaceShader': Parse error: syntax error, unexpected TVAL_RGBAFLAGS, expecting TOK_SETTEXTURE or '}'