GET question mark is not excaped in custom url when concatenated after an empty token

I encountered trivial edge case bug, that i wanted to document.

I'm using the field group link in a paragraph bundle containing a link field
if the fieldgroup link is a Custom URL with a token concatenated with an get parameter (eg. ?test)
and the the token result is empty

eg :
[paragraphs_item:field-paragraph-link:display_url]?test
but the field pargraph_link is empty

then the link is generated but the "?" is not escaped and is then replaced by
/%3Ftest
instead of /?test (on the current url) here on homepage)
which leads to a 404

If the field field-paragraph-link is not empty, then the href is ok and get is escaped correctly
giving something like
/myurlvalue?test