[BUG]: Output and preview mismatch with shader + merge

Bug Description

Opening the following file produces a much whiter preview than the output in node graph.

dziwnawoda.zip

Steps how to trigger the issue

1. Open the attached file (unzip it first)
2. Go into node view
3. Observe the mismatch between output and preview

How did you download the software?

Steam

Version Channel

Stable

Version Number

2.1.2.3

Operating System

Windows

OS Version

Windows 10

Additional Context

The nodes manipulating noise could be removed to simplify the setup.

Code of Conduct

• I agree to follow this project's Code of Conduct