CSV import fails when file contains hash character and quoted multi-line value

JIRA's CSV parser fails given a particular format of valid CSV, with the error:

Failed to read CSV file, you may decide to ignore the error: java.io.IOException: Malformed CSV stream. Missing ["] near offset 3 after field 0 on line 3

The CSV in question is:

Summary,IssueType,CustomField
Test #1,Bug,"foo
bar"

What causes this CSV to fail is the hash character, followed by the multi-line quoted string.

To replicate:

1. atlas-run-standalone --product jira --version 5.0.5
2. Log in as admin/admin and create a test project (mine is called TST)
3. Save the above CSV to a file.
4. Try to import the CSV into your project. The configuration doesn't matter, but with my TST project I used the config file:

   {
     "date.import.format" : "yyyyMMddHHmmss",
     "project.name" : "Test Project",
     "field.IssueType" : "issuetype",
     "project.lead" : "admin",
     "project.key" : "TST",
     "user.email.suffix" : "@example.com",
     "mapfromcsv" : "false",
     "field.Summary" : "summary"
   }
   

5. After submitting the "Set up field mappings" form, you will see the error message above: