I cannot reproduce this issue with UltraEdit for Windows v2022.1.0.90. The substring highlighting worked in my test.

Please compress the *.uew file used for syntax highlighting the SQL files and an example SQL file with 7-Zip, RAR or ZIP and attach the archive file to your next post so that I can review the wordfile.

I don't know anything about the syntax of Teradata SQL. So it could be that some decisions made on fixing the syntax highlighting wordfile are not good.

The attached ZIP file contains now the two wordfiles TeradataSQL.uew and TeraDataUtil.uew with following corrections and improvements.

1. Added /Delimiters = to both wordfiles to define the word delimiting characters instead of depending on internal defaults of UltraEdit. The internal default changed obviously as the underscore is interpreted by UltraEdit v2022.1.0.90 and v2022.1.0.100 as word delimiter which was not the case before. I will ask support of UltraEdit if that change in default list of word delimiters is intentionally or by mistake. The definition of the word delimiters in both wordfiles fixes the problem with substring highlighting. The delimiters list is  based on the operators list as I don't know the TeraData SQL syntax fixes.
2. Moved the syntax highlighting language Teradata Utilities into a separate wordfile required if ever using in future smart language templates.
3. There was by mistake Line Block Line Comment = instead  of just Line Comment = in first line of both language definitions. In second language definition was even used wrong double quotes around this definition.
4. Sorted the file extensions alphabetically for better readability (not necessary for UltraEdit).
5. Removed all (?i) from the Perl regular expression search strings as this flag for a case-insensitive search is not necessary because of UltraEdit runs the searches for the strings to show in Function List always case-insensitive. See also Case sensitivity of Perl regular expressions in UE/UES.
6. Removed all color and font style settings not read anymore from the *.uew files since UltraEdit for Windows v20.00. The color and font style settings of a syntax highlighting language are stored in the theme file of the used UltraEdit theme.
7. Resorted all words in all color groups which fixes also the wrong word definitions of words starting with different character on same line like for /C2"Operators" in TeradataSQL.uew.
8. Added / to color group for operators in TeradataSQL.uew.
9. Fixed invalid word definitions like ."HELP BTEQ" or ."SHOW CONTROLS" containing the word delimiter space. It is impossible to define a string for syntax highlighting containing a word delimiter. There is one exception. The first character of a word or substring can be a word delimiter. I suppose the double quotes do not really exist in files with extension ARC FLD MLD.
10. Removed the substring definition ${ as there is already in same color group the substring definition $ to syntax highlight all strings starting with a dollar sign.
11. Removed on some color groups the space between the color group number and the color group name enclosed in double quotes.

There is a remaining issue with TeradataSQL.uew which still contains the invalid substring definition \&& in color group 7. The characters \ and & are defined both as word delimiter. This substring definition is invalid for that reason. There can be removed either this substring definition or the character & is removed from the line beginning with /Delimiters =. I don't know what is better for TeraData SQL syntax highlighting.

Color group 2 in TeraDataUtil.uew should get also a meaningful name for better identification in the Manage Themes window on customizing the colors and font style for this color group.

Please let me know after fixing the last issue if there is still something not syntax highlighted as wanted by you and I will try to find a solution for you with the provided example.

Update: UltraEdit for Windows v2022.1.0.112 and UEStudio v2022.1.0.112 released on 2022-10-05 interpret an underscore again as word character and not as word delimiter if the used syntax highlighting wordfile does not contain /Delimiters = to explicitly define the word delimiters.