Civil War historian here. I have not ever heard any mention of anything like that happening. The big issue at the end of the war was seeking an alternate labor pool for agriculture in the South.

Most of what I've seen shows that many slave owners were genuinely surprised that their slaves wished to leave the plantation at the end of the war. Many slave owners had convinced themselves that their slaves were happy with their conditions.

What I've read conforms with what u/expostfacto-saurus mentioned. One thing I would add is that the CSA government passed the Impressment Act in March 1863, which forced slave owners to give a certain percentage of their workforce over to the government for wartime use (usually for menial labor) using a promise of eventual reimbursement. Many salve owners marched their slaves west, and further south in an effort to keep the slaves out of sight, and away from Confederate agents looking to extract the government's "due." It's thought that thousands of slaves died during these marches. I know this isn't exactly what the OP asked about, but it seemed related.

[Sources: Douglas Ball, 'Financial Failure and Confederate Defeat'; Shelby Foote, 'The Civil War: A Narrative, vol. 2']

Some follow up questions:

Wouldn't this instantly become a murder charge?

Would any authorities actually prosecute?

Were slave owners able to kill their slaves legally (I know they wouldn't want to) before slavery was abolished?

Slaves that "stayed" did they just start receiving a paycheck of some form? (After slavery was abolished)

Edit: making last question clearer.

Been in the Storm So Long: The Aftermath of Slavery, is a Pulitzer Prize winning book, and I'm moving right now so I can't pull it out and quote directly from it, but it is suggested that many male slave owners were not even on the plantations when slavery was abolished because they were off fighting the war and those that were had guns and were able to defend themselves against unarmed former slaves. A few had to ask the Union army to send soldiers to help however, and you know they must have felt their lives were in danger if you can picture a Confederate doing that. Some female slave owners fled their plantations altogether out of fear, but there appears to have been less animosity against them in general. I can't honestly remember for sure if the book mentioned if any of the owners were killed, however, some overseers were murdered and there are details as to where, when and how. Regardless, the vast majority of former slaves were not interested in retaliation. Other than basic questions of "how do I live now" many were just trying to find their family members that had been taken from them.

If it happened, what would be the rationalization for doing that?

Question beside this. Did slaves, after getting their freedom, try to go back to Africa?

Edit: homelands as in, I remember hearing it wasn't only Africans that were enslaved. Editied it to not sound as wierd.