[NetScaler] Squid may record "error:transaction-end-before-headers" when be the service of LB

In a NetScaler Load Balancing deployment, you may have a Squild proxy server configured as a NetScaler LB Service. And you may observe "error:transaction-end-before-headers" recorded on Squid server. The error apears periodically with several seconds interval. Log sample: Timestamp xxxx...