My Setup:

• LimeSurvey Version 3.17.9+190731
• Windows Server 2016 + IIS 10.0
• MS SQL Server 2017

In my surveys the default token length was always set to 36.
When I generate the tokens an SQ error occurs, because the max length of the token-length-column is 35 (not 36).

500: Internal Server Error
CDbCommand konnte das SQL-Statement nicht ausführen: SQLSTATE[22001]: [Microsoft][ODBC Driver 17 for SQL Server][SQL Server]String or binary data would be truncated.
An internal error occurred while the Web server was processing your request.

Workaround: Change the token length in each survey manually.

Then I found the following code in surveyadmin.php starting from line 2099:
if ($iTokenLength > 36) {
$iTokenLength = 36;
}

My issue did not appear anymore after I changed the above code to:
if ($iTokenLength >= 36) {
$iTokenLength = 35;
}

KR,
Alex