Hi Patrick,
My name is Erin, and I'm on the Moz Help Team. Thanks for reaching out! This question is a little tricky, as I can't see any historic page level data from OSE. All I can check is historic domain level data within your campaign. I looked at your historic data in your Competitive Link Metrics, and I didn't see any dramatic change there to reflect this kind of a drop in your LDR's.
We are kicking around ideas on better historical databases, but there's nothing set in stone right now. Currently the only data points we have are based on domains in the current index. I apologize that I don't have a more concrete answer for you, but this is the best I've got with the tools available to me.
If you have any other questions, feel free to reach out to us at help@moz.com.
Happy Friday!
Erin
Don't worry about your GA data, it's stored safe and sound within GA. You won't lose any data when your profile disconnects.