method:OPTIONS call shows up Earlier than method:GET in the Waterfall

I’m running the test on a SPA application. For a Single Page Application, in order to make CORS requests, we all know that the method:OPTIONS call for any Service call will happens first and then the corresponding method:GET/POST call happens.

When I run my tests, sometimes (not always) in the Waterfall, in the Details, the GET and the OPTIONS seem to be interchanged.



Clearly also the tike taken by the OPTIONS call will be very low as compared to the GET/POST call.
Can someone help with why this behaviour is observed intermittently?
Thank you in advance