<?php $url = $modx->makeUrl($id, '', 'param=3'); ?>
[[~id? ¶m=`3`]]
[[~4? &c=`1`]]
http://localhost:8888/bild-worte/galerie.html?c%3D1
Any chance you could enter a ticket in JIRA for this one so it doesn’t get overlooked before release?
Though "%3D" means "=" in URLs so it’s not completly inexplicable. It’s a bug!