As Resolver session contains non-MavenWorkspaceReader, the reactor models (already resolved w/ profiles applied) are re-built when using Resolver within Mojo, instead to get them via ReactorReader as expected. The rebuilt models will lack explicit (-P on CLI) profiles applied, as resolver itself is not maven aware, hence there is no way to "tell" resolver to apply them. Building reactor models w/ profiles applied is NOT done using resolver, but by Maven when loading up reactor, as profiles are NOT applied for downstream transitive dependencies (see discussion on MNG-1388 why).
The README of the following reproducer says it all:
Initially discussed here: https://github.com/quarkusio/quarkus/pull/24285#issuecomment-1067368625