19489 Socket-GTInspector-Instance-of-LinkedList-did-not-understand-key

I've bumped into a minor glitch ticketed with the GTInspector embedded
in the debugger.
https://pharo.fogbugz.com/f/cases/19489

Henrik has kindly tried to reproduce it but was unable.  But he is on
Windows and I'm on Linux.
Could someone on Linux take 10 minutes try to reproduce the following...

Open fresh build 60334.
Load the ST file attached to issue,
then in playground, do this once...
  s := Server new.
  s start. "listens on port 9999"

and this once for each trial...
  socket := Socket newTCP.
  [
      socket
        connectTo: NetNameResolver localHostAddress
        port: 9999;
        sendData: 'test'.
  ] ensure: [ socket closeAndDestroy ]

This brings up an expected debugger (okay)
"ShouldBeImplemented: #newFromStream: should have been implemented in
Packet class"

From top stack select Packet class>>newFromStream:
then select variable aSocketStream,
then in next pane, select #isConnected,
then click on [Raw] tab,
and I get an error "Instance of LinkedList did not understand #key"

Now a few times the error did not occur, but did >90% of the time.
cheers -ben