Invisible Vindicator

After dying to a vindicator, on my way to get my items back I kept getting attacked by an invisible vindicator

What I expected to happen was...:
The vindicator not turn invisible after i died to it

What actually happened was...:
The vindicator turned invisible after I died to it

Steps to Reproduce:
1. Kill the raid leader*
2. Die to a not invisible vindicator
3. That not invisible vindicator will turn into an invisible vindicator.

*not sure if killing the raid leader has had any affect on it.

The glitch got fixed after I left the world and got back in.