Path pattern matching / - restkit

Question

I'm trying to build a response descriptor for calls to the Dropbox metadata API.
Using the DBMetadata class from the Dropbox OS X SDK, here is my mapping:
RKObjectMapping *metadataMapping;
metadataMapping = [RKObjectMapping mappingForClass:[DBMetadata class]];
[metadataMapping addAttributeMappingsFromDictionary:#{#"thumb_exists": #"thumbnailExists",
#"bytes" : #"totalBytes",
#"modified" : #"lastModifiedDate",
#"client_mtime": #"clientMtime",
#"path" : #"path",
#"is_dir" : #"isDirectory",
#"hash" : #"hash",
#"size" : #"humanReadableSize",
#"root" : #"root",
#"icon" : #"icon",
#"rev" : #"rev",
#"revision" : #"revision",
#"is_deleted" : #"isDeleted"}];
[metadataMapping addRelationshipMappingWithSourceKeyPath:#"contents"
mapping:metadataMapping];
Here is my Response Descriptor (As much as I'd like to, I can't use :root:path, see NOTE 1):
RKResponseDescriptor *metadataResponse;
metadataResponse = [RKResponseDescriptor responseDescriptorWithMapping:metadataMapping
method:RKRequestMethodGET
pathPattern:#"metadata/dropbox:path"
keyPath:nil
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
[self.manager addResponseDescriptor:metadataResponse];
The manager is setup as:
NSURL *baseAPIURL = [NSURL URLWithString:[NSString stringWithFormat:#"%#://%#/%#/", kDBProtocolHTTPS, kDBDropboxAPIHost, kDBDropboxAPIVersion]];
self.manager = [RKObjectManager managerWithBaseURL:baseAPIURL];
self.manager.requestSerializationMIMEType = RKMIMETypeJSON;
The problem is that the #"metadata/dropbox:path" path pattern always fails:
DBMetadata *root;
root = [[DBMetadata alloc] initWithDictionary:#{#"root": #"dropbox",
#"path": #"/"}];
[self.manager getObject:root
path:#"metadata/dropbox/"
parameters:#{#"list": #"false"}
success:...
failure:...];
Result:
E restkit.network:RKObjectRequestOperation.m:213 GET
'https://api.dropbox.com/1/metadata/dropbox/?list=false' (200 OK / 0
objects) [request=0.0957s mapping=0.0000s total=0.0968s]: Error
Domain=org.restkit.RestKit.ErrorDomain Code=1001 "No response
descriptors match the response loaded." UserInfo=0x6000000ee900
{NSLocalizedFailureReason=A 200 response was loaded from the URL
'https://api.dropbox.com/1/metadata/dropbox/?list=false', which failed
to match all (0) response descriptors:,
NSErrorFailingURLStringKey=https://api.dropbox.com/1/metadata/dropbox/?list=false,
NSErrorFailingURLKey=https://api.dropbox.com/1/metadata/dropbox/?list=false,
NSUnderlyingError=0x6000000569b0 "No mappable object representations
were found at the key paths searched.", keyPath=null,
NSLocalizedDescription=No response descriptors match the response
loaded.}
But if I set the path pattern in the response descriptor to a static string (#"metadata/dropbox/"), it works:
I restkit.network:RKObjectRequestOperation.m:220 GET
'https://api.dropbox.com/1/metadata/dropbox/?list=false' (200 OK / 1
objects) [request=0.1027s mapping=0.0014s total=0.1034s]
Is it not possible to pass "/" as a path pattern parameter?
I also noticed that the error says that the response failed to match all (0) response descriptors. Shouldn't it be (1) in this case?