At this time, we are not aware of any issues with the error check for zip code, so it is unclear what may be prompting the message you are receiving.
Without a look in your account at a particular listing where this issue is occurring it is difficult to say what may be prompting the message, you refer to. In order to look into this for you, it would be best if we could review your account and some of the affected listings.
If you have not already done so, please file a support case from under the Help tab of the site, ensuring that your username is included as well as the title of a listing or two where this occurs for you and our support agents will be happy to look into it for you.
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