Wrong names in Windows?

PS D:\git\github.com\gunnarmorling\1brc> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      7.3.10
PSEdition                      Core
GitCommitId                    7.3.10
OS                             Microsoft Windows 10.0.22621
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

PS D:\git\github.com\gunnarmorling\1brc> scoop install temurin21-jdk maven
...
PS D:\git\github.com\gunnarmorling\1brc> mvn clean verify
...

PS D:\git\github.com\gunnarmorling\1brc> java --version
openjdk 21.0.1 2023-10-17 LTS
OpenJDK Runtime Environment Temurin-21.0.1+12 (build 21.0.1+12-LTS)
OpenJDK 64-Bit Server VM Temurin-21.0.1+12 (build 21.0.1+12-LTS, mixed mode, sharing)
PS D:\git\github.com\gunnarmorling\1brc> chcp
Active code page: 437
PS D:\git\github.com\gunnarmorling\1brc> chcp 65001
Active code page: 65001
PS D:\git\github.com\gunnarmorling\1brc> $OutputEncoding

Preamble          :
BodyName          : utf-8
EncodingName      : Unicode (UTF-8)
HeaderName        : utf-8
WebName           : utf-8
WindowsCodePage   : 1200
IsBrowserDisplay  : True
IsBrowserSave     : True
IsMailNewsDisplay : True
IsMailNewsSave    : True
IsSingleByte      : False
EncoderFallback   : System.Text.EncoderReplacementFallback
DecoderFallback   : System.Text.DecoderReplacementFallback
IsReadOnly        : True
CodePage          : 65001


PS D:\git\github.com\gunnarmorling\1brc> $Env:JAVA_TOOL_OPTIONS = "-Dfile.encoding=UTF8"

PS D:\git\github.com\gunnarmorling\1brc> java --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CreateMeasurements 1000000000
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8
Wrote 50,000,000 measurements in 17124 ms
Wrote 100,000,000 measurements in 34366 ms
Wrote 150,000,000 measurements in 51380 ms
Wrote 200,000,000 measurements in 68445 ms
Wrote 250,000,000 measurements in 85397 ms
Wrote 300,000,000 measurements in 102491 ms
Wrote 350,000,000 measurements in 119489 ms
Wrote 400,000,000 measurements in 136484 ms
Wrote 450,000,000 measurements in 153494 ms
Wrote 500,000,000 measurements in 170461 ms
Wrote 550,000,000 measurements in 187471 ms
Wrote 600,000,000 measurements in 205101 ms
Wrote 650,000,000 measurements in 222205 ms
Wrote 700,000,000 measurements in 239340 ms
Wrote 750,000,000 measurements in 256477 ms
Wrote 800,000,000 measurements in 273675 ms
Wrote 850,000,000 measurements in 290896 ms
Wrote 900,000,000 measurements in 307993 ms
Wrote 950,000,000 measurements in 325116 ms
Created file with 1,000,000,000 measurements in 342196 ms
PS D:\git\github.com\gunnarmorling\1brc> java --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage >result.txt
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8

PS D:\git\github.com\gunnarmorling\1brc> ug -m1 -o "Ab.ch." src/main/java/dev/morling/onebrc/CreateMeasurements.java measurements.txt result.txt
src/main/java/dev/morling/onebrc/CreateMeasurements.java
    80: Abéché

measurements.txt
   527: Abéché

result.txt
     1: AbΘchΘ

PS D:\git\github.com\gunnarmorling\1brc> ug --hexdump -m1 -o "Ab.ch." src/main/java/dev/morling/onebrc/CreateMeasurements.java measurements.txt result.txt
src/main/java/dev/morling/onebrc/CreateMeasurements.java
    80:
00000cc0  -- -- -- -- -- -- -- --  -- -- -- -- 41 62 c3 a9  |------------Ab..|
00000cd0  63 68 c3 a9 -- -- -- --  -- -- -- -- -- -- -- --  |ch..------------|

measurements.txt
   527:
00001c10  41 62 c3 a9 63 68 c3 a9  -- -- -- -- -- -- -- --  |Ab..ch..--------|

result.txt
     1:
00000030  41 62 ce 98 63 68 ce 98  -- -- -- -- -- -- -- --  |Ab..ch..--------|