service reply template with link into prefilled field forms does not work as expected

Hi

I have created a very basic questionary form in superoffice and an idea is, that when our customer server sends out an email where is a link into our questionary form, an existing customer email should be ready as prefilled field. For that we are using variable [[customer.email]].

Link in reply template looks as follows:
https://ourserver/cs/scripts/customer.fcgi?action=formFrame&formId=xxxxxx&field_email=[[customer.email]]​

When customer clicks on the link, form looks like it should with prefilled email address in it and visually it looks ok.

But when i look reporting from forms, i can see, that user has not be recognized and it requires some action in order to link it into correct customer.
I tested the same without prefilled fields, so customer needs to type an email address manually and then it work correctly. Then i checked a link on reply message (with prefilled field) and notice, that there is some additional text behind email address. I removed it manually and then it worked correctly again. 
Here is the link and additional text at the end of the link:

https://ourserver/cs/scripts/customer.fcgi?action=formFrame&formId=xxxxxx&field_email=ingar.molder@grano.fi%E2%80%8B

So my question is, how can i get rid of the additional text behind an email address. 
Thanks for you help
regards
Ingar