I came on this one by accident actually since I had accidentially exploded the sun twice when I meant to select the second time.
Steps:
1. start new sim and place the sun, pause the sim
2. set the explosion speed to 100 (though it also happened with the initial which was either speed of 1.00 or 10.00).
3. set power to explode and click the sun twice.
4. Timestep probably makes no difference, I had it on about a minute/s and 10 sec/s and it did that there. Unpause. I noticed that it'll still do the error even when paused.
It's not as bad as the other error spam I reported, but error spam is still error spam.
Also, even at max explosion power, it's still not enough to shatter the sun, it just coalesces back together.