I tested with the following configuration and I did not reproduce an issue with the specific cultures
<localization defaultProvider="Sitefinity" persistenceMode="PathPrefix" allowSpecificCultures="true" defaultCulture="en" cultures="en, fr, de, bg, en-ca, en-us, es">
Please check if there are js errors thrown when you try to publish a page. If you use another type of persistenceMode you can switch to PathPrefix to see if the problem comes from this attribute.
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