I was able to reproduce it locally outside of dbuild by publishing Scalameta 4.8.3 locally for 2.13.12-bin-a11bacd, then running sbt -Dscala.nightly=2.13.12-bin-a11bacd and reflect2_13/doc
sbt:scalafix> reflect2_13/doc
[info] Main Scala API documentation to /Users/tisue/scalafix/scalafix-reflect/target/jvm-2.13/api..
[error] /Users/tisue/scalafix/scalafix-reflect/src/main/scala-2/scalafix/internal/reflect/RuleCompiler.scala:46:21: not enough patterns for object Info offering (scala.reflect.internal.util.Position, String, reflect.internal.Reporter.Severity, List[scala.reflect.internal.util.CodeAction]): expected 4, found 3
[error] case reporter.Info(pos, msg, reporter.ERROR) =>
[error] ^
[error] one error found
[error] stack trace is suppressed; run last reflect2_13 / Compile / doc for the full output
[error] (reflect2_13 / Compile / doc) Scaladoc generation failed
[error] Total time: 0 s, completed Jul 14, 2023, 2:57:07 PM
oh, I should have looked a little closer before even opening a ticket, it's the List[scala.reflect.internal.util.CodeAction] having been added, of course
I was able to reproduce it locally outside of dbuild by publishing Scalameta 4.8.3 locally for 2.13.12-bin-a11bacd, then running
sbt -Dscala.nightly=2.13.12-bin-a11bacd
andreflect2_13/doc