It certainly seems to coincide with/relate to updates of OneDrive for me.
The new version gets downloaded to %appdata%..\local\microsoft\onedrive\xx.xxx.xxxx.xxxx however, whatever update process then occurs seems to preclude bothering to put onedrive.exe back in the %appdata%..\local\microsoft\onedrive
folder.
What usually tips me off is the Windows Defender Security Center prompting for me to set up OneDrive... or noticing that there are no longer green sync'd indicators on something I'm working on.
Running the %appdata%..\local\microsoft\onedrive\xx.xxx.xxxx.xxxx\OneDriveSetup.exe works for me, but is a pain in the backside. It does however put the onedrive.exe where it should be.
My system is a completely Microsoft affair. Microsoft Surface Book. Microsoft Windows. Microsoft Office (O365). Windows Defender. Microsoft OneDrive. Makes it a Microsoft issue to resolve. Quickly. Please.