Jira Potfolio shows invalid entry for a date when language is different then English

Summary

Jira Portfolio shows invalid entry for a date written in language different then English since Portfolio does not support I18n as of now.

Environment

Cloud

Steps to Reproduce

1. Edit the Due Date field of an issue from the Portfolio plan
2. For example, in German, enter 15/Mai/17 in the field

Expected Results

The date is saved

Actual Results

Date shows as invalid

Notes

This works as expected in JIRA

Workaround

Use the date picker to select the date. The date will be saved in English, for example 15/May/17
Type in the date in English