To protect against malicious web sites, Outlook.com uses Safelinks which adds characters to a URL and converts all 1-byte special characters into 3-byte hex codes.
An account recovery e-mail from Google contains an embedded URL which is very long. When the URL is processed through Safelinks it ends up being over 2048 characters long. When you try to click on the recovery URL (or use copy/paste), and the URL is decoded from its Safelinks version, the URL is truncated after 2048 characters and is rejected by Google as invalid. The only workaround is to manually decode all the 3-byte hex codes in the portion of the URL beyond 2048 characters.