From a few years back, but still relevant.
I worked for a very large company for ten years, and because of my role and tenure, I had a longer notice period than usual. Three months instead of 4 weeks.
When I handed in my resignation, I managed to negotiate that down to eight weeks—I had built up a decent amount of good will and wasn’t leaving on bad terms.
Three weeks after I left, my work buddy called me crying with laughter. When he could talk, he told me to check my bank account. I was super confused, but I did it and then asked him “how the fuck is that possible?”
Turns out nobody told HR about the amended finish date, and they paid me for an extra month.
His exact words: “dude I was in that meeting and they’re gonna send you a request for repayment BUT the HR people said because of a High Court decision that’s as much as they are allowed to do. If you spend it right now they’re completely screwed”
Called my new boss (one of the genuine good ones), he cracks up laughing and says “go for it dude”
Had a lovely week at a five star place in Crete, and a bunch of new Converse.
The company never wrote to me again.
Key point: “my position has changed regarding that money” DO NOT GIVE IT BACK