webfileupload demo fail

Hi ,
I am in troubled about webfileupload fail.

I run demo project in xojo 2018R4 sample “WebFileUploader”. (on OSX Sierra 10.12.6)
From Safari (12.0.2) two file upload ==> OK.
But only one file up load ==> NG.

Details:
From Safari , click “+” in FileUploader1 , and select one file . ex. “aaa.png”
first of row in ListBox1 , change to “Add aaa.png”
then click UploadButton , first of row in ListBox1 , change to “Upload 1” and UploadProgress is in action.
After this , No change .

in IDE messeage :
1:56:10 : Unhandled OutOfBoundsException
Message:
Stack:
RuntimeRaiseException
_Z19RaiseExceptionClassRK13ClassDeclBase
memoryGetString
MemoryBlock.StringValue%s%oi8i8o
_WebMemoryBuffer.Read%s%o<_WebMemoryBuffer>u8s
_HTTPServer.HTTPRequestContext._LoadMultipartVariables%%o<_HTTPServer.HTTPRequestContext>s
_HTTPServer.HTTPRequestSocket._HandleRequest%%o<_HTTPServer.HTTPRequestSocket>
_HTTPServer.HTTPRequestSocket.Event_DataAvailable%%o<_HTTPServer.HTTPRequestSocket>
SSLSocket.dylib$3191
SSLSocket.Event_DataAvailable%%o
_ZN9TCPSocket10FireEventsEv
_ZN14TCPSocketPosix4PollEv
_Z9DoNetIdleh
rbframework.dylib$5900
_Z22TriggerBackgroundTasksh
rbframework.dylib$10228
_Z11ModalEventsh
RuntimeDoEvents
ConsoleApplication.DoEvents%%oi8
WebApplication.Event_Run%i8%oA1s
_Z36CallConsoleApplicationRunEventHelperv
ConsoleApplication._CallFunctionWithExceptionHandling%%op
_Z33CallFunctionWithExceptionHandlingPFvvE
RuntimeRun
REALbasic._RuntimeRun
_Main
main

If I select two or more , it is OK .
row in ListBox1 , change to “aaa.png uploaded” and “bbb.png uploaded”

please someone help.

Thank you for reading my poor English sentences.

As a result of spending time translating it using google and writing it here,
the only thing I have noticed is that nobody is here.
Good forum community.

I can’t reproduce what you are seeing on my computer, but the stack trace seems to indicate that the data that was transmitted is smaller than was stated in the request. That probably shouldn’t crash though.

Does this happen with all files? Or just with the specific files you are trying?

Thank you Grag reply.
By Japanese customer support advice , i recognized difference of webuploader control behavior between XOJO 2017 and 2018.

I think that the type of file does not matter.

And I tried 100 times , and i got a result.
In my env , size of file less than 523998byte is fail.

523998byte OK
523997byte NG

The test use fill repeat char “a” . just text file.

safari and chrome , debug mode and build standalone ==> same result .

Do you have anything to think about?