Load average tick script

I added load1 rule similar to mem_alert_stream.tick
I have mem and cpu alerts. My dashboards show me load metrics and load alert generated with chronograf works as well (though it works in strange way; I get Critical host1 and then Ok host2 and it repeats while it is critical for host1).

So here is my alert rule, what can be wrong?

// Parameters
var info = 0.5
var warn = 0.7
var crit = 1
var infoSig = 2.5
var warnSig = 3
var critSig = 3.5
var period = 10s
var every = 10s

// Dataframe
var data = stream
  |from()
    .database('telegraf')
    .retentionPolicy('autogen')
    .measurement('system')
    .groupBy('host')
  |window()
    .period(period)
    .every(every)
  |mean('load1')
    .as('stat')
    
// Thresholds
var alert = data
  |eval(lambda: sigma("stat"))
    .as('sigma')
    .keep()
  |alert()
    .id('{{ index .Tags "host"}}/load1')
    .message('{{ .ID }}:{{ index .Fields "stat" }}')
    .info(lambda: "stat" > info OR "sigma" > infoSig)
    .warn(lambda: "stat" > warn OR "sigma" > warnSig)
    .crit(lambda: "stat" > crit OR "sigma" > critSig)

// Alert
alert
  .log('/tmp/load1_log.txt')