Unexpected extra error message

import * as Schema from '@effect/schema/Schema';
import { Config, ConfigError, Effect, Either, Layer, Logger } from 'effect';

export const logger = Logger.make(a => {
    globalThis.console.log(JSON.stringify(a));
});

const DebugOutputFormat = Schema.literal('JSON', 'Readable');
type DebugOutputFormat = Schema.Schema.To<typeof DebugOutputFormat>;

const debugOutputFormat = (name: string): Config.Config<DebugOutputFormat> => {
    const config = Config.mapOrFail(Config.string(), value => {
        return Schema.parseEither(DebugOutputFormat)(value).pipe(
            Either.mapLeft(() =>
                ConfigError.InvalidData(
                    [],
                    `Expected a debug output format of 'JSON' or 'Readable', but found: ${value}`,
                ),
            ),
        );
    });
    return Config.nested(config, name);
};

export const LoggerLive = Layer.merge(
    Effect.config(Config.logLevel('DEBUG_LEVEL')).pipe(
        Effect.map(level => Logger.minimumLogLevel(level)),
        Layer.unwrapEffect,
    ),
    Effect.config(debugOutputFormat('DEBUG_OUTPUT_FORMAT')).pipe(
        Effect.map(format =>
            Logger.replace(Logger.defaultLogger, format === 'Readable' ? Logger.defaultLogger : logger),
        ),
        Layer.unwrapEffect,
    ),
);