I'm sorry, that was a misunderstanding. I didn't mean you could actually fix the issue by removing the parameters from the url because, in fact, Merconis adds them and has to do so. What I meant was that if you remove the paramters from the url temporarily (in the address field of your browser) you can see that without them it would work. However, the way Merconis adds those parameters is perfectly fine and in all our test cases this didn't cause any problems whatsoever.
The conclusion from this observation is that in your project there's probably something that reacts overly sensitive to these path-like parameters in the url when creating the breadcrumb navigation. And that's where unfortunately I can only quote from my last post:
Since the breadcrumb navigation is a basic contao module, the issue most likely isn't related to Merconis. There could be a number of things that might affect the breadcrumb navigation, for example a custom breadcrumb navigation template or other third party extensions etc.
So, if you have a custom breadcrumg navigation template you should start by looking at that. If you can't find anything there and you have any third party extensions besides Merconis you could try to disable them and look if that changes something. If that doesn't work either, you could play around with some contao settings that are somehow related to navigation creation.
Please let us know, if you can find something.