Transformation of an object into parameter value on submission of request

Today I saw rather a weird phenomeon, when submitting a request spontaneoulsy.

The URL I typed looked something like below: and when submitted it transformed into

If I correctly perceived that the pro object moved to a value of layout (if not just visually).

It didn’t work for and when submitted should transform into, that didn’t work.

It did only work for the pro object.

Is this a behavior made by developers of the site or could this eventually lead to something interesting?