MAUI Android publish fails: missing System.Activator.CreateDefaultInstance #12921

Description

MAUI Android performance CI jobs fail when publishing MauiAndroidDefault.csproj with UseMonoRuntime=true.

Error

Unhandled exception. System.InvalidOperationException:
Expected method 'CreateDefaultInstance' not found on type
'[S.P.CoreLib]System.Activator'

error NETSDK1096: Optimizing assemblies for performance failed.

The stack trace includes ILCompiler.ReadyToRunCodegenCompilation (which is weird for Mono...)

Environment

Expected and actual behavior

Expected: The configured Mono performance scenario publishes successfully.

Actual: Crossgen throws the exception above, and publish fails with NETSDK1096. The underlying cause is not yet confirmed.

CI evidence

• Build 3087066: Mono Pixel10a job: the same error affects the GalaxyA16 and Pixel8 Mono jobs.
• Build 3086879: Mono Pixel10a job: the same error affects the GalaxyA16 Mono job.

The corresponding Default CoreCLR jobs pass in both builds. CI links require internal Azure DevOps access.