Browse sort errors

I have two that tags that aren't recognised correctly by LMS. When I browse, "Bach, JS" is listed between "Tadd..." & "Tafel..." and "Bartók" is listed between "New Lon…" & "New Yor…".

If I change "Bach, JS" to "Bach, J.S." or to "Bach, Js" and change "Bartók" to "Bartok" the list is then sorted correctly. However, the characters are all recognised and displayed correctly and Björk is listed correctly.

The behaviour is consistent for all albums with the same tag and happens on both my players. The tags were created under dBpoweramp. I have checked Extended Tags in Mp3tag but can't see any clues. If I select a track in the LMS web interface and drill down to View Tags all I see is, for example:

ACCURATERIPDISCID: 029-004466d1-056db57b-b70fb91d-1
ACCURATERIPRESULT: AccurateRip: Accurate (confidence 8) [4A6ABB80]
ALBUM: Sketches & Dances
ALBUMARTIST: Budapest Festival Orchestra, Hungarian Radio Chorus, Iván Fischer
ALLPICTURES: [ HASH(0x86c6070) ]
ARTIST: Bartók
CATALOG #: 454 430-2
COMMENT: Béla Bartók
COMPOSER: Bartók
CONDUCTOR: Ivan Fischer
DATE: 1997
DISCNUMBER: 1
DISCTOTAL: 1
ENCODED BY: dBpoweramp Release 14.4
ENCODER: (FLAC 1.2.1)
ENCODER SETTINGS: -compression-level-5
GENRE: Modernist
LABEL: PHILIPS
ORCHESTRA: Budapest Festival Orchestra
PERIOD: Modern
SOURCE: CD (Lossless)
STYLE: Symphonic
TITLE: Hungarian Peasant Songs, Ballad
TRACKNUMBER: 1
TRACKTOTAL: 29
VENDOR: reference libFLAC 1.2.1 20070917

---

Logitech Media Server Version: 7.9.2
piCorePlayer 4.1.0
Squeezelite v1.9.0-1121-pCP
RaspberryPi ZeroW + RaspberryPi 3A+