Quick tasks or action like refresh take more or less time to execute.. ih they execute.

For exemple, il I select a device and make a refresh from zcc it is possible the refresh executes immediatly.
If a take another device that is of course connected and make the same action it can takes several minutes to end but sometimes I get a time out and it failed.
Same when I want to Install or Launch a bundle directoy to a device. Sometimes it is working and sometimes it does not...

Anyone know why?