The agent is triggering the Software Distribution Check. Any packages that are assigned to be installed at that time, that have not yet been installed, will be downloaded and installed. So failed packages should retry at next Software Distribution Check that occurs within this time window.
If a Software Distribution Check runs outside of this time then no attempt will be made. However, if the Software Distribution Check happens, say, 1 minute before the end of the time window, the download and installations will start and will continue until completed; so software could still be installing beyond the set window.
That is what I thought that agent will reinstall it once it checks in. Thank you for the confirmation.