I am using the amplitude Javascript SDK. Following the documentation: at https://help.amplitude.com/hc/en-us/articles/115003135607-Tracking-Unique-Users I assumed Amplitude sdk would by itself set up a single device id (as the name suggests) for the computer that I use and would send the same device id for any browser I use (unless I set a custom userId with setUserId method). Not only it sends different deviceIds for different browsers, it also sends regenerates device id for any tab/session.
How can I prevent it from happening?
I have contacted the Amplitude support, there was a bug in the amplitude SDK. As stated in the question, DeviceId should not be changed when we open a new tab or reopen the window within the same browser and user (not incognito).
Updating the amplitude sdk version from 6.2.0 to 7.1.0 solved this problem!