http proxy. max-cache-size is not work

Good day!
Router OS 4-beta2 on X86. Http-proxy:
/ip proxy
set always-from-cache=no cache-administrator=root cache-hit-dscp=4
cache-on-disk=yes enabled=yes max-cache-size=200KiB
max-client-connections=5000 max-fresh-time=3d max-server-connections=5000
parent-proxy=0.0.0.0 parent-proxy-port=0 port=3128 serialize-connections=
no src-address=%^.$#.@#.%$
/ip proxy access
add action=allow comment=“” disabled=no src-address=10.0.0.0/8
add action=deny comment=“” disabled=no src-address=0.0.0.0/0
/ip proxy cache
add action=deny comment=“” disabled=no path=“:cgi-bin \?”

I set max-cache-size=200 , but after 1-2 hour of work cache-size more 20 Mbytes

/ip proxy> mo
status: running
uptime: 1w2h6m10s
requests: 3763549
hits: 1179190
cache-used: 41990KiB
total-ram-used: 10946KiB
received-from-servers: 67874638KiB
sent-to-clients: 64410934KiB
hits-sent-to-clients: 8659188KiB


and in ‘insert’ no ‘no memory’ errors:
/ip proxy> mo
status: running
uptime: 1w2h6m10s
requests: 3763549
hits: 1179190
cache-used: 41990KiB
total-ram-used: 10946KiB
received-from-servers: 67874638KiB
sent-to-clients: 64410934KiB
hits-sent-to-clients: 8659188KiB

set max-cache-size=10 and see - maybe this value is in megabytes =)

No, no limit-s, may be in Gb ?