Login links from my service were automatically clicked and rendered and I know that other services discovered similar problems. Based on this I think that it is

Login links from my service were automatically clicked and rendered and I know that other services discovered similar problems. Based on this I think that it is very likely the case with all the links in emails, but I don't know if there is any additional heuristic involved that would treat some links differently. See also this issue which suggests that all links are opened: https://techcommunity.microsoft.com/discussions/microsoftdefenderforoffice365/possible-major-problem-with-ms-defender-scanningclicking-links/3874918 https://techcommunity.microsoft.com/discussions/microsoftdef... Note that this doesn't affect all Outlook users, this Microsoft Defender for Office 365 is a separate product that only some companies use.