diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index 20ae236700..a99489f7fd 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -344,10 +344,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 		$principals = $this->principalBackend->getGroupMembership($principalUriOriginal, true);
 		$principals = array_merge($principals, $this->principalBackend->getCircleMembership($principalUriOriginal));
 
-		$principals = array_map(function ($principal) {
-			return urldecode($principal);
-		}, $principals);
-		$principals[]= $principalUri;
+		$principals[] = $principalUri;
 
 		$fields = array_values($this->propertyMap);
 		$fields[] = 'a.id';
diff --git a/apps/dav/lib/DAV/Sharing/Backend.php b/apps/dav/lib/DAV/Sharing/Backend.php
index 2f8fb0c310..c77e90b961 100644
--- a/apps/dav/lib/DAV/Sharing/Backend.php
+++ b/apps/dav/lib/DAV/Sharing/Backend.php
@@ -107,6 +107,7 @@ class Backend {
 			return;
 		}
 
+		$principal[2] = urldecode($principal[2]);
 		if (($principal[1] === 'users' && !$this->userManager->userExists($principal[2])) ||
 			($principal[1] === 'groups' && !$this->groupManager->groupExists($principal[2]))) {
 			// User or group does not exist