Deleting a namespace and then bringing it back and populate it does not work as expected

[aplteam]

Starting point is the file Code.zip

Download this, unzip into, say, /path/2/, start 19.0 and carry out the following steps:

1. ]Link.Create '#.Code' /path/2/Code
2. Execute #.Code.Create
3. Execute #.Code.test_1

This always results in:

FILE ACCESS ERROR: /path/2/Code/_667/Foo: Unable to open file
test_1[3] ⎕SE.Link.Add'#._667.Foo.'∘,¨↓#._667.Foo.⎕NL 3

After executing "Resume all threads" (that's right!) you get something along these lines:

Added: #._667.Foo.Fns_00 #._667.Foo.Fns_01 ...
Link Warning: FileSystemWatcher error on directory: /path/2/Code/_667 watching may no longer be reliable.
FILE ACCESS ERROR: /path/2/Code/_667/Foo: Unable to open file
      test_1
      ∧

At this stage, when I enter )SI, 100% of the time APL hangs.

(This is my <02264>)

[aplteam]

]Tools.Version
 Dyalog  19.0.51424 64-bit Unicode, BuildID f0edb773 
 OS      Windows 11 (10.0.26100) 64-bit              
 Link    4.0.20                                      
 SALT    2.915                                       
 UCMD    2.6                                         
 .NET    .NET Framework 4.8.9310.0                   
 WS      19.0                                        
 Tatin   0.120.0                                     
 Cider   0.48.0    

[dyavc]

aplteam has reported that these issues don't happen with Link 4.1.4. I am trying the repro. We regard the hang as a Dyalog issue and I am getting more info about that.