strange scheduler problem, scripting

[gjniewenhuijse]

Since last week, without script changes i have a strange problem. My script doesn't run as expected.

First my script is planned at 12:00 but runs at 13:00, why?

script:

Code:

cInterval = 24*60*60 --every 24 hours

myobjects = grp.tag('update_chk1')
for index, value in ipairs(myobjects) do
 diff = (os.time() - value.updatetime)
 if (diff >= cInterval or value.data == false) then    
   if value.data then
      log('brandmelder check: '..diff..' >= '..cInterval..' true')
    else
      log('brandmelder check: '..diff..' >= '..cInterval..' false')
   end
 end
end

And then it generates a line in the log: 
log value: brandmelder check: 2194 >= 172800 true


That's not true, because 2194 < 172800 and value.data == true

What do i wrong?