Compiler version

The issue seems to be reproducible with all Scala versions starting from 3.4.1.
All Scala versions from 3.4.0 and below (including 2.12 and 2.13) seem to be OK.

Minimized code

Whatever produces a deprecation warning, for example:

//> using scala 3.4.1
//> using options -Werror

object A {
  @deprecated("this one is deprecated", "ever")
  def imdeprecated() = ()

  imdeprecated()
}

Note: -deprecation is not provided.

Output

there was 1 deprecation warning; re-run with -deprecation for details
1 warning found

and the compilation succeeds(!).

Expectation

All Scala versions from 3.4.0 and below fail here:

there was 1 deprecation warning; re-run with -deprecation for details
1 error found
Compilation failed

Additional Context

Adding -deprecation changes the behavior (actually, fixes it): the compilation fails with all Scala versions.
In other words, the issue seems only to appear when -deprecation is missing.