https://www.alteraforum.com/forum/attachment.php?attachmentid=11215
I am not that familiar with the External_Clocks module that is instantiated in the Qsys system. I don't think they come with Qsys library but rather that comes together with the DE Quartus project. You need to find the hw.tcl file in your local directory. Try to find the avalon_clock_slave and set the proper reset association. Something like:
set_interface_property avalon_clock_slave "associatedReset" "reset"
The "reset" is replaceable by the reset interface being declared in the hw.tcl.