Mario (at CF7 to Webhook (aka Zapier)) has fixed the issue with a new v2.2.2 update. If anyone else is experiencing issues with special mail tags and using CF7 to Webhook after the CF7 v5.2.1 update, you might want to update the CF7 to Webhook plugin. Mario just pushed out his update version 2.2.2. Thanks for your help Takayuki.