Steps to replicate

1. Create a test project
2. Create version ('v1.0' for example)
3. Create an issue in your test project and enter 'v1.0' in the fixversion field. Don't select the autocomplete option, just click anywhere else on the screen
4. Hit Create Issue

Result:

Error is thrown with message

'Version with id 'v1.0' does not exist.

This happens despite the content being highlighted as if it completed successfully.

Expected Result

Issue is created successfully

Issue is not browser specific, happens in current versions of Firefox, Chrome and Safari