Received this response on 07/20 for my help ticket:
I would like to inform you that we are aware of the issue and we are investigating this issue with our Engineering team and we will get back to them once we have a update from the Engineering team.
Last time I received an unusual activity detected for MS IP 13.101 variation was 07/19 4:32pm CST. However, I did find a successful sync from today at about 6:42pm CST for IP: 2a00:1450:4864:20::626. When I looked this IP up, it says it belongs to RIPE Network Coordination center out of Amsterdam!!
https://whois.arin.net/rest/net/NET6-2A00-1/pft?s=2a00%3A1450%3A4864%3A20%3A%3A626
Clicked the secure your account link, and it tells me I have already secured my account since this activity occured. Which isn't the case. So I had to manually go in and change my password.
Cuz who the hell is RIPE from Amsterdam, and why are they syncing with my account.
From what I can find: The RIPE NCC is one of five Regional Internet Registries (RIRs) providing Internet resource allocations, registration services and coordination activities that support the operation of the Internet globally. We're an independent, not-for-profit membership organisation that supports the infrastructure of the Internet through technical coordination in our service region. Our most prominent activity is to act as the Regional Internet Registry (RIR) providing global Internet resources and related services (IPv4, IPv6 and AS Number resources) to members in our service region.
It seems like Microsoft is tied to them somehow. But I don't understand how. Best guess is MS purchased and is using some of the IPv6 addresses from RIPE, and this is still a MS IP doing some weird sync to my account. It's all a little above my paygrade. Changed my password to be safe. If after I change my password, they sync with me again, then I guess I'll have my answer that it's definitely tied to MS.