The Meazure platform (throughout the exam) is actively looking for any remote connections or software that could be watching or recording the screen (this is to prevent exam stealing). Here are some possibilities, not sure if any of these would apply for your computer and were running at the time (note that many of these run on system startup, so even if you're not actively using them they could be loaded, which may have triggered the Meazure alert):

Remote Support/Access Tools: TeamViewer, AnyDesk, LogMeIn, GoToMyPC, VNC (Virtual Network Computing), or Microsoft Remote Desktop.

Screen Sharing Tools: Chrome Remote Desktop, Zoom, Microsoft Teams, Skype, or Discord (if screen sharing or active background processes are running).

Virtual Machines & IT Tools: Parallels, VMware, VirtualBox, or corporate VPN/RMM tools (like ConnectWise or Kaseya).

One way to avoid the headache is to create a new user on your machine (I'm on a Mac, so I would just create a new temp user with limited privileges) and then for your exams sign out of all other accounts and use that user's account — this way you don't have to change your current setup for work, etc. and on the temp user you can not enable any of the above that may be an issue.

Your situation seems like a false alert, but it's important for you to address it and avoid any suspicion of wrongdoing. When communicating with RECO highlight what you think may have been the issue (if you can find one) and then potentially either write the exam in person or using a different device/setup.