Is there an event id / log / log source for when an ip, gateway, netmask changes in Windows 10?
You aren't going to get an event for IP/Gateway/Mask without a custom script that generates an event whenever one of these properties change. But you can find events for when the IP is changed via DHCP.
To get DHCP events, you must enable the following log in the Windows Event Viewer (eventvwr.msc):
Event Viewer / Applications and Services Logs / Microsoft / Windows / Dhcp-Client / Microsoft-Windows-DHCP Client Events/Operational
Once enabled, you will see EventID 50029 stating "Address xxx.xxx.xxx.xxx is unplumbed" when an IP is removed and EventID 50028 stating "Address xxx.xxx.xxx.xxx is plumbed" when an IP is added. There are other debugging events showing the interface ID and the DHCP server IP.