ClustalW erroneously detects alignment alphabet as "Extended amino acid"

Scenario:

1. Open the WD.
2. Create the following workflow: "Read Alignment" > "Align with ClustalW" > "Write Alignment".
3. Select "Read Alignment" and input file "sequenceAll_2lineformat.fasta" (the file can be found on the file server in the users dataset folder).
4. Run the workflow.
   Current result: after reading of the data from the file (this takes about a minute) the workflow finishes. There is the following status on the WD dashboard:

   The workflow task is in progress. There are problems...
   

   There are the following error messages in the UGENE log:

   [ERROR] Unsupported alphabet: Extended amino acid
   [ERROR] Nothing to write
   

   Note that the alignment is quite big and an error notification appears on an attempt to open it in the Alignment Editor.
   However, the "sequenceAll_2lineformat.fasta" file does not contain sequences with "Extended amino acid" alphabet. Each sequence contains only characters from:

   ABCDEFGHIKLMNPQRSTVWXYZ*-
   

   Thus, the error description is incorrect.
   Expected result: ClustalW should either finish successfully or return a more meaningful and correct error.