Hello,
The " is a Unicode character and will only be shown in the CSV file of the report. That is because the CSV file will separate each column with,”column data”, “Next column data”
So in the CSV the column “Wert” is between Quotes (Anführungszeichen) like
"Wert=https://monstergadgets.de/produkt/rospec-dampfglaetter-1200w/"
When you check the XML feed itself you see that the ULR is not ending with an "
It still is a bit weird because the Unicode should be just real Quotes (Anführungszeichen) like ”
Besides that, the URL looks good and I do not see why it should be invalid.
If you resubmit the feed to Google, the same feed you have posted here. Is the feed generating issues? Could you let me know what the error tells you in the Merchant center itself? Not in the CSV report but in the Merchant center self?