STREAM::expression matches on single char only

What does the logging says? Does it even find the string?

Would it be possible to try below iRule to see if this makes any difference just for testing?

when RULE_INIT {
        set static::stream_response_body
        {
                 "AUSEFPPKI03====ZZ.ZZ"
		 "ausefppki03====ZZ.ZZ"
 
        }
	}	
 
when HTTP_REQUEST {
    STREAM::disable
    HTTP::header remove "Accept-Encoding"
} 
 
 
when HTTP_RESPONSE {
        if {[llength $static::stream_response_body] > 0}
        {
                set expression ""
                foreach stream_request_rewriteRecord $static::stream_response_body
                {
                        set stream_request_find [getfield $stream_request_rewriteRecord "====" 1]
                        set stream_request_replace [getfield $stream_request_rewriteRecord "====" 2]
                        if {$stream_request_replace == "nothing"}
                        {
                                set stream_request_replace ""
                        }
 
                        set expression "$expression@$stream_request_find@$stream_request_replace@"
                }
                if {[HTTP::header Content-Type] contains "text" } {
                        if { [catch
                        {
                                STREAM::expression $expression
                                STREAM::enable
                        } result] }
                        {
                                #log local0. "fffffffffff $result"
                        }
                }
        }
  }