See some of the configurations in the associated answerhub:
https://answers.unrealengine.com/questions/710975/material-static-switch-broken-in-nested-functions.html
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-50878 in the post.
| 0 |
| Component | UE - Graphics Features |
|---|---|
| Affects Versions | 4.17, 4.18, 4.19 |
| Target Fix | 4.19 |
| Created | Oct 6, 2017 |
|---|---|
| Resolved | Oct 16, 2017 |
| Updated | Apr 27, 2018 |