Bug? Failed build command: Clean.Remove clean build/B4iProject.build/Release-iphoneos/B4iProject.build

[Sandman]

I got this error after doing some very minor changes in the code, and trying to compile it for debugging. I tried compiling again (with no changes to code/libs/etc) and that worked just fine.

I suppose I must have hit a very small edge case, nothing too important. I'm mostly posting this for completeness, in case Erel is working on something on the backend and can use this as input for something.

B4i Version: 4.40
Parsing code.    (0.10s)
Compiling code.    (0.82s)
Compiling layouts code.    (0.03s)
Compiling debugger engine code.    (3.54s)
Building Xcode project    (0.64s)
Sending data to remote compiler.    Error
Out: === CLEAN TARGET B4iProject OF PROJECT B4iProject WITH THE DEFAULT CONFIGURATION (Release) ===

Check dependencies
[BCEROR]Code Signing Error: Code signing is required for product type 'Application' in SDK 'iOS 11.2'

Create product structure
/bin/mkdir -p /Users/administrator/Documents/UploadedProjects/<user id>/build/Release-iphoneos/B4iProject.app

Clean.Remove clean build/B4iProject.build/Release-iphoneos/B4iProject.build
    builtin-rm -rf /Users/administrator/Documents/UploadedProjects/<user id>/build/B4iProject.build/Release-iphoneos/B4iProject.build
Error Domain=NSCocoaErrorDomain Code=513 "“B4iProject.build” couldn’t be removed because you don’t have permission to access it." UserInfo={NSFilePath=/Users/administrator/Documents/UploadedProjects/<user id>/build/B4iProject.build/Release-iphoneos/B4iProject.build, NSUserStringVariant=(
    Remove
), NSUnderlyingError=0x7fed747e2db0 {Error Domain=NSPOSIXErrorDomain Code=66 "Directory not empty"}}
Command builtin-rm failed with exit code 513

Clean.Remove clean build/Release-iphoneos/B4iProject.app
    builtin-rm -rf /Users/administrator/Documents/UploadedProjects/<user id>/build/Release-iphoneos/B4iProject.app


Error: ** CLEAN FAILED **


The following build commands failed:
    Clean.Remove clean build/B4iProject.build/Release-iphoneos/B4iProject.build
(1 failure)