[Bug]: Müllmax arguments seem to be shared incorrectly with source

[makanimike]

I Have A Problem With:

A specific source

What's Your Problem

With the new update, going to the GUI based source configuration, it appears to me that there is an issue with entering arguments for Müllmax.
https://github.com/mampfes/hacs_waste_collection_schedule/blob/master/doc/source/muellmax_de.md

I had my arguments running perfectly fine for a couple of years (in the yaml file). With the latest update I simply copypasted those args into the new GUI tool. But then I get the following error message:

The source returned an invalid response: "Got invalid response from the server, please recheck your arguments". Please check the provided arguments and try again.

The arguments needed are (as per the example):
- name: muellmax_de
args:
service: Fes
mm_frm_str_sel: Achenbachstraße
mm_frm_hnr_sel: 60596;Sachsenhausen;2;

Just like in the example, my personal location does not have mm_frm_ort_sel.
Both my actual address, as well as the example address throw the same error message.

I suspect that the new GUI is submitting the arguments in some incorrect way? (I think the technical term might be that it is parsing it incorrectly?)

Source (if relevant)

No response

Logs

No response

Relevant Configuration

- name: muellmax_de
      args:
        service: Fes
        mm_frm_str_sel: Achenbachstraße
        mm_frm_hnr_sel: 60596;Sachsenhausen;2;

Checklist Source Error

• Use the example parameters for your source (often available in the documentation) (don't forget to restart Home Assistant after changing the configuration)
• Checked that the website of your service provider is still working
• Tested my attributes on the service provider website (if possible)
• I have tested with the latest version of the integration (master) (for HACS in the 3 dot menu of the integration click on "Redownload" and choose master as version)

Checklist Sensor Error

• Checked in the Home Assistant Calendar tab if the event names match the types names (if types argument is used)

Required

• I have searched past (closed AND opened) issues to see if this bug has already been reported, and it hasn't been.
• I understand that people give their precious time for free, and thus I've done my very best to make this problem as easy as possible to investigate.