Netscaler log file /var/log/ns.log might be getting filled with similar log entries: 

Jun 29 09:27:27 <local0.notice> X.X.X.X 06/29/2017:08:27:27 GMT ns1 0-PPE-0 : default ICA Message 346352927 0 : "NS_ICA_ERROR: Invalid buffer length file no = 1489 line no = 2" 
Jun 29 09:27:27 <local0.notice> X.X.X.X 06/29/2017:08:27:27 GMT ns1 0-PPE-0 : default ICA Message 346352928 0 : "NS_ICA_ERROR: Invalid buffer length file no = 4258 line no = 2" 

This can cause excessive logging on the syslog server and /var/log/ns.log files are filled with the same logs. 

Note: there is no impact on the production but the excess amount of logs are preventing users to track issues from NetScaler logs or extracting reports from the logs.

To resolve this issue, upgrade the appliance:

• for NetScaler release 12.0, upgrade to build 51.24 MR (or later).
• for NetScaler release 11.1, upgrade to build 54.16 (or later).

Workaround

> set syslogParams -logLevel EMERGENCY ALERT CRITICAL ERROR WARNING INFORMATIONAL

Note: Using the preceding command will stop the logging from other modules as well as the syslog parameters will be disabled for all the NOTICE related logs thus resulting in stopping of NOTICE log forwarding.

Problem Cause

These type of verbose logging is triggered on App/ Desktop launch when HDX Insight is enabled on the Netscaler.