No I actually contacted them because the 55 is too heavy for the mount I was going to use. The CS agent said "are you not happy with the 55" and told me there is no option to return it for replacement with a 50". They basically said keep it or return for refund. I spend a ton with Amazon every year and this isn't something that's out of the ordinary TBH. I've been sent 1000w PSU's when I ordered an 850, etc. When I ordered a 2x SVS SB1000 Pros and decided 1 was good enough, they told me to just keep the 2nd and refunded me. They've been really good to me.And Amazon hasn't contact you regarding it?? Huh, sounds like a nice little surprise.
As for the rainbow effect yeah it's definitely there but only really visible in specific scenarios so not a deal breaker.
I'm going to borrow my friend's 50" to see how it stacks up since he's busy with his G9 Neo.