V26 Breaks builds and does not give accurate error. Solution inside.

Ok we just had the whole team debugging this for a full day. We only found it by deleting huge parts of our project until it worked.

Original Behavior:

Observed Result

LogHttp: Warning: Lockout of 10.000000s on https://content-service.bfda.live.use1a.on.epicgames.com/api/content/v2/artifact/d0fac710-c14d-4a50-ae33-71ff9bac29dc%3Apc/cooked-content
LogHttp: Warning: Retry 1 on https://content-service.bfda.live.use1a.on.epicgames.com/api/content/v2/artifact/d0fac710-c14d-4a50-ae33-71ff9bac29dc%3Apc/cooked-content
LogHttp: Warning: Lockout of 10.000000s on https:

Error
We encountered an error prepairing your projects
Job_ID=f3c05443-ba8d-46ec-bd84-8b3714633fe8
Too many warnings/ errors, aborted processing of errors/warnings

After Deleting Huge Parts of our product we got the following errors

Turns out the only actual issue was a post effect material.

We only discovered this by process of elimination.