Hi Amandeep Kumar,
First, I have "Hide dock icon when the main window is closed" selected. But the icon in the dock is not hidden, it is just not active (no more dot under the icon). In the images below, the 1st one is with the enpass window open, in the second one the window is closed.
After a system restart, when the enpass window is opened you can see 2 icons. And the active enpass icon is not the latest one to show up (on the right), but the one that was active before the restart (on the left):
The 2 icons are still seen after the enpass window is closed again:
After opening/closing the enpass window a few times, I can see more than 2 enpass icons in the doc. This time, the active icon is the latest one that showed up (on the right side):
It does not seem to create several enpass icons at once, as it was the case a few years ago. Let me know if you need more information.
Note that I have only the last 8 recent applications showing up in the dock.