Has Been Fixed or Is Fixed?

Technically speaking, "the issue is fixed" means "somebody fixes the issue". And "the issue has been fixed" means "somebody has fixed the issue". So, the correct usage in all probability should be "the issue has been fixed".

Was fix or fixed?

If something is fixed somewhere, it is attached there firmly or securely. If you fix something, for example a date, price, or policy, you decide and say exactly what it will be. If you fix something for someone, you arrange for it to happen or you organize it for them.

Have fixed meaning?

From Longman Dictionary of Contemporary English have fixed ideas/opinions to have very definite ideas or opinions that you will not change – often used to show disapprovalhave fixed ideas/opinions about/on He has very fixed ideas about how a wife should behave. → fixed.