Big Sur / Can't open windows from finder properly, but works on terminal

Describe the bug
When I open a .tex file on MacVim from the Finder's level (just by clicking on a file), I get an error:

On the other hand, when I open the file form terminal, ie. mvim <file_name> it opens properly and every plugin works, as on MacOS Catalina. This strange behaviour emerged when I updated MacOS.

To Reproduce
As written above:

1. I open a file from Finder - error pops out and actually nothing works (just like it was disconnected from anything that is installed and configured by .vimrc)
2. When I open a file from terminal using mvim everything works as it should.

Expected behavior
No such errors, consistency between opening from terminal and finder.

Environment (please complete the following information):

• Vim version: VIM - Vi IMproved 8.2
• MacVim version: MacVim 8.2.1719 (up to date)
• OS: macOS Big Sur
• Terminal: GUI, Terminal.app

Additional context
It emerged after system update from Catalina to BigSur.
I have MacVim installed from .dmg file.

Beginne damit, MacVims Finder-Startpfad mit dem Pfad im Terminal über mvim zu vergleichen, wobei der gemeldete Unterschied beim Laden von .vimrc und die Umgebung MacVim 8.2 als Reproduktionsgrundlage dienen. Bestätige das Verhalten unter macOS Big Sur und verfolge anschließend den Einstiegspunkt für den GUI-Start, bis dasselbe konfigurierte Verhalten aus dem Finder ohne Fehler funktioniert.