We have been talking about address poisoning hack on this forum. It happens in a way hacks create an address similar to your altcoin address. It has happened to me when I was sending coins like USDT and some other altcoins which are not stable coins. But I understand about it and I easily avoided copying the address I sent coin to, instead I go to the receiving wallet or exchange to copy the address. You can know the hacker's address by noticing small amount not worth up to $1 sent to you with the hacker's address. If you check the address, it will be similar to your address but not you address. Avoid sending coins to the address. I do not know if it happens with bitcoin too, but I have not seen it while sending bitcoin. But if sending any coins, check the address you are sending to, make sure it is the same as the address you are sending to.
Thanks OP , You have shared a valuable information with us and I hope no one will be lazy after reading your post. Checking while address will not take more than 2 minutes as Hugeblack mentioned , and It will save our fund. Usually this scam attempt happening in PC where malware attack is responsible for all these scam.
Some hackers are very smart, when you paste address, you will see the same address you copied but when you check approve pop up then address will be change. My address was hacked in this method but I found it before approving.