I have reproduced this on 37 different ASE instances, distributed among 19 different physical servers. Some are Solaris, some are Red Hat, and some are Windows. The ASE versions are all 15.0.3, either ESD #2, 3, or 4. (Most are Solaris 15.0.3 ESD#2.) Same result whether client is isql or SQL Advantage.
Typical @@version is:
Adaptive Server Enterprise/15.0.3/EBF 16736 ESD#2/P/Sun_svr4/OS 5.8/ase1503/2707/64-bit/FBO/Sun Jul 26 10:29:50 2009
In 35 of the 37 cases, my sp_helpsort gives this:
Character Set = 2, cp850
Code Page 850 (Multilingual) character set.
Sort Order = 41, dictionary_cp850
General purpose dictionary sort order for use with several Wes
tern-European languages including English, French, and German.
Uses the Code Page 850 character set and is case-sensitive.
In two cases, I get this:
Character Set = 1, iso_1
ISO 8859-1 (Latin-1) - Western European 8-bit character set.
Sort Order = 51, dictionary_iso_1
General purpose dictionary sort order for use with several Wes
tern-European languages including English, French, and German.
Uses the ISO 8859-1 character set and is case-sensitive.
I believe I am using a case insensitive sort order. Perhaps that's what it takes to expose this bug.