Playing 1.16.5 Version (This has happened twice)
When I exit the nether the witherstorm cannot be seen
No chunks are forceloaded like they should be around the storm
/kill @e[type=witherstormmod:wither_storm] does nothing
Another one has to be spawned in order to work
One time I did this the witherstorm was still alive it just unloaded but I can't confirm that for the second time

Are you using the latest 1.16.5 version of the mod?

Were you using OptiFine? If so, "Smooth World" probably was the culprit. Also, has this issue occured mutliple times?

Closing until this issue can be reliably reproduced.

Yes

Will have to investigate then