RSTP topology changes are generated when a non edge port comes up. If you are using the default trunk native vlan 1 configuration for all your access ports you could be generating a load of TCN's.   Please configure all ports that go to endpoints as access ports.  Meraki software enables edge port / portfast automatically on access ports.  Edge ports do not generate TCN's when they come up.   If this is not the case then there must be a part of the L2 domain in your network that actually does have unstable STP topology.  Make sure you really check out the entire network. ... View more