Question about: "rate-limit: stop limiting responses to 1.1.1.0/24 for www.example.com"

[Tom]

Hi list

I'm testing rate-limits (BIND 9.11.2) and I'm unsure, how I've to 
understand the following "stop-limiting"-log-entry:
1)
04-Jan-2018 15:09:10.852 rate-limit: info: limit responses to 1.1.1.0/24 
for www.example.com IN A  (7ae73d9b)

2)
04-Jan-2018 15:09:10.852 rate-limit: info: client @0x7f16440ee550 
13.93.86.165#55203 (www.example.com): rate limit drop response to 
1.1.1.0/24 for www.example.com IN A  (7ae73d9b)

3)
04-Jan-2018 15:09:16.773 rate-limit: info: client @0x7f16440fcc30 
13.93.86.165#33997 (www.example.com): rate limit drop response to 
1.1.1.0/24 for www.example.com IN A  (7ae73d9b)

4)
04-Jan-2018 15:10:20.266 rate-limit: info: stop limiting responses to 
1.1.1.0/24 for www.example.com IN A  (7ae73d9b)


- #1-#3 seems clear, because they reaches the configured threshold. But 
what about the entry #4? Why does this logentry only appears about 60-65 
seconds later, after I've stopped the "test"-attack (confirmed multiple 
times..)?

My rate-config:
	rate-limit {
		responses-per-second 5;
		slip 0;
		window 5;
	};


Many thanks.
Kind regards,
Tom