Import a string of numbers into a Date Type attribute will result in wrong value

Issue Summary

Using a JSON or CSV import, Dates which are stored in source as a string of numbers, will be treated as UNIX Timestamp

Insight 8.7.6

Steps to Reproduce

1. In an Object Type, add a Date type Attribute
2. Create a CSV or JSON source / file to import, and make sure to have a column for dates formatted as yyyyMMdd, e.g. 20200316 
3. Configure an Import for this source, and indicate the date format yyyyMMdd in the Import Configuration.
4. Map the Date column to the Date Attribute
5. Synchronize the import

Expected Results

The date value will be imported and interpreted per the Date Format, and the value displayed in the Attribute will show according to the Date Picker in Jira

Actual Results

The date will show a wrong value, for example: 22 Aug, 1970 or 22.08.70

Which matches the value calculated if treating 20200316 as a UNIX Timestamp

...

Workaround

If possible - try and add separators to the source value, and indicate them in the Date Format configuration, for example:
2020.03.16
And the date format: yyyy.MM.dd