self as default content via link doesn't bring plusses

I made a link that sends the name of the current card (_left) to a new card as the default content for a tag on the new card (making a comment card that tags the card I was reading). However, when the _left content (e.g. hummus+recipe) appears as a tag in the new card, it appears with the plusses replaced with spaces (e.g. "hummus recipe"), which makes it useless.