Sigil is starting with two instances on Mac OS

Hi,

i'm not pretty sure if this is a Sigil issue or not, but as i have this only with Sigil i would lkike to start here.

I told my MacBook to connect epub Files not with iBooks but with Sigil. I did this with some other applications as well without an problems (jpg and raw => affinity, mp3 => clementine).

But what now happens (not a big issue)

Double clicking on an epub files starts Sigil twice: One instance contains the selected epub, the other is showing just the initial epub (as when you start the app itself).

Did someone else countered such a behaviour? I mean its not a big deal to close the second instance as this is always in front, but i successfully did that for all other applications i have without any issue at all.

Best Regards
Maui