The issue is due to the use of "Options" field in the TCP header. Refer to the following example of an ADN enabled packet capture:
The size of the "Options" section is showing a high value of 36 bytes. This is due to the addition of ADN information by using this field. A normal TCP packet will have a size up to 20 bytes for "Options".
This issue doesn't happen for all websites; very few are known to have this issue. The root cause can be due to server incompatibility or a security device blocking modified TCP packets in case of a potential security threat.