New filter returns double filter on select

-- url of the page with the problem -- : www.1stopmotoronderdelen.nl/banden
-- HikaShop version -- : 3.4.1
-- Joomla version -- : 3.9.8

I allready have a filter working correctly on my products, so should know how it all works. But I ran into some strange problems which I will try and explain here.

I created custom fields (band_breedte, band_hoogte, band_diameter, band_merk, band_belasting as 'single dropdown') and added all the possible values in there.
Then created filters for each custom field, and the filters show correctly.
Imported (for now) 2 different items with different specifications and when I open the page, the filters and 2 products show correctly.

ISSUE 1:
when I open the product in the front end, it shows the custom fields vallues as specifications for the product correctly.
when I open the product in de backend, the fields are shown, but don't show the values as stored in the database..... huh..... but default values (even thow I didn't define a default value in the filter...). When I save and close, these 'default' values are stored....
If I change the custom fields to TEXT, the values in the backend show correctly.

ISSUE 2:
when I select one of the values in the filters on the front end, the page returns with 2 times the filter row and no products ......

ISSUE 3:
the first 3 filters correctly show the values that can be selected, the next two filters (band_merk and band_belasting) don't show any value even though the value is correctly set in both database, and custom field attribute

I have a feeling the issues might be related to each other.
I know I'm down on hikashop version, but as the other filter I have setup works just fine, this one should obviously work as well.

I added some screenshots to clarify....

After a good night sleep I continued with the issue.....

After another import from some different products, I found that my categorie was created again with a space in front. So changed the import file to have the categorie name directly after the comma.....
Then it hit me.... all my fields started of with a space after the comma. For the numbers that is not an issue, but if you have text in the field there is no exact match with the ones I inserted in the custom fields......

Changed the script that generates my import file and now all looks fine.....

I was right that the issue was due to one 'mistake'.....

Hopefully it helps anybody else that runs into something similar.

Yes, no problems anymore, so subject can be closed.