It's because the program you are using to translate IPv6 to IPv4 is wrong. You can't just take the last 4 bytes of an IPv6 address and turn it into IPv4. That's not how IPv6 works.
Yes, I saw you posted this in another thread, checked it, and found that it's just taking the last 4 bytes of the IPv6 address, and turning it into IPv4. That's not correct. Not all IPv6 addresses can be turned into IPv4.
I will try to explain IPv6 and IPv4 a bit, I hope you'll try to understand what I'm trying to say.
IPv4 is 32-bits long. This means there can be a total of 2^32 IPv4 addresses in the world. That's 4,294,967,296 total. That's not a lot. And as you can imagine, we ran out after a while.
As a result, IPv6 was created. IPv6 addresses are 128-bits long. That means there can be 2^128 of them. I'm not going to try to write out this number, suffice it to say, it is way, way bigger than the number of IPv4 addresses.
Here's the problem: since there are way more IPv6 addresses than IPv4 addresses, the majority of IPv6 addresses can't be converted to IPv4 addresses.
What the script you used is doing, is it takes the 128-bit IPv6 address, completely ditches the first 96-bits, and uses the last 32-bits to convert to IPv4. That is not valid.
Here's how you can verify that I'm correct. You were converting fe80::792b:3e74:df1b:c565, and the script told you it translates to 223.27.197.101. Now try a totally different address, keeping only the last 32-bits, say, 0000::0000:0000:df1b:c565. See what you get.
It's because the program you are using to translate IPv6 to IPv4 is wrong. You can't just take the last 4 bytes of an IPv6 address and turn it into IPv4. That's not how IPv6 works.
Yes, I saw you posted this in another thread, checked it, and found that it's just taking the last 4 bytes of the IPv6 address, and turning it into IPv4. That's not correct. Not all IPv6 addresses can be turned into IPv4.
In fact, if you read the code, you see the comment at the top sends you to this Stackoverflow answer: https://stackoverflow.com/a/23147817/11404332
The explanation is there as well.
I will try to explain IPv6 and IPv4 a bit, I hope you'll try to understand what I'm trying to say.
IPv4 is 32-bits long. This means there can be a total of 2^32 IPv4 addresses in the world. That's 4,294,967,296 total. That's not a lot. And as you can imagine, we ran out after a while.
As a result, IPv6 was created. IPv6 addresses are 128-bits long. That means there can be 2^128 of them. I'm not going to try to write out this number, suffice it to say, it is way, way bigger than the number of IPv4 addresses.
Here's the problem: since there are way more IPv6 addresses than IPv4 addresses, the majority of IPv6 addresses can't be converted to IPv4 addresses.
What the script you used is doing, is it takes the 128-bit IPv6 address, completely ditches the first 96-bits, and uses the last 32-bits to convert to IPv4. That is not valid.
Here's how you can verify that I'm correct. You were converting fe80::792b:3e74:df1b:c565, and the script told you it translates to 223.27.197.101. Now try a totally different address, keeping only the last 32-bits, say, 0000::0000:0000:df1b:c565. See what you get.