IP address changing DURING passive ftp session

Hi there @JeremyR   Thank you so much for reaching out.  It seems your FTP sessions are failing due to your IP address changing during the connection, which may be caused by Comcast's network policies. To resolve this, ensure that your business has a static IP address and consider contacting Comcast to verify your network configuration. Additionally, check if your FTP host can whitelist your static IP to prevent blocking. If issues persist, consult with your email or network administrator for further assistance in maintaining a stable connection.  Click the link below for more info.  

https://www.xfinity.com/support/articles/list-of-blocked-ports

Glad I found this, me too. 

• I pay for a static IP block
• Oct 20 324am my network drops for 6 minutes (Presumably CBR2 updates being applied)
• Oct 20 330am 1.5% of my network requests show as coming from my routers dynamic wan address, not from my static address
• Oct 21 315am my network drops for another 6 minutes
• Oct 21 321am the error is no longer there 

The reproduction of the failure was pretty simple:

  req_resp=requests.get(IP_CKECK_API)
  logging.info(req_resp.text)
  time.sleep(.5)

This would return the wrong IP 1.5% of the time, using various "What is my IP" APIs from AWS, Cloudflares, ifconfigme and the likes. All showed the same error rate. 

Public IP              Requests    Percent
--------------------------------------------
7.the.dynamic.wan.ip      1206      1.56%
ERROR                     30      0.04%
5.my.static.ip            76017     98.40%
--------------------------------------------
TOTAL                     77253    100.00%

This did get fixed in this morning's update they rolled out.. But I wanted to leave a note here too since this type of "wrong ip being sent" bug had a huge impact on my business' security policies.