Clicking on navbar links collapses the link texts briefly

[AiyionPrime]

To reproduce this, click on the second navbar item "Kontakt" to avoid this bug being shadowed by #89.

Clicking an item in the navbar, which links an anchor on page triggers a "collapsing"-class to be added to the navbar elements, which makes them look like a tube television powering off for a brief period of time.

If anyone has an idea to resolve this, I wasted a few hours on this matter Thursday evening,
my next approach would be to rewrite the navbar in BS5 and have a look at what differences lie in my implementation. I'd like to avoid that. Maybe someone has a sharper eye.

I think this bug was introduced in the Bootstrap 4->5 transition.