How to reproduce:
1. Open user's attached "StackLitShaderNodeSpecularOcclusionModes" project
2. Open the "StackLit Shader Graph.shadergraph"
3. Open the "StackLit Master" settings by pressing the cog at the top of "StackLit Master" node
4. Change the "Specular Occlusion" option from "Off" to "Direct From AO"

Expected result: The RGBA port of the Sample Texture 2D node and the Normal port of the StackLit Master node stay connected
Actual result: The RGBA port of the Sample Texture 2D node and the Normal port of the StackLit Master node get disconnected

Reproducible with: 7.2.0 (2020.1.0a26, 2020.2.0a11), 7.4.1 (2019.4.1f1, 2020.1.0a26, 2020.2.0a11). 8.1.0 (2020.1.0b6, 2020.2.0a15)
Not reproducible with: 7.1.8 (2020.1.0a26, 2020.2.0a11)

Notes:
- Happens only when something is connected to the "Normal" in the "StackLit Master" doesn't happen when connecting to the other options
- The connection gets deleted when changing these settings in the "StackLit Master": Surface Type, Distortion, Auto Clipping, Fragment Normal Space, Anisotropy, Coat, Iridescence, Transmission