The Fiverr Paypal invoice is definately not valid.
It contains only "fiverr.com" as the seller name. It doesn't contain their company name and adress.
Domain names are not legal entities and cannot issue invoices. Also their company name is not fiverr.com, but Fiverr Interntaional Limited, however their company name is not found on the invoice.
And there is no way to tell where this invoice is coming from, from which country. They don't disclose that they are located in Israel. So you cannot check the validity of this invoice. For example there are countries where the electronic invoices must be signed digitally by the issuer and must have a digital time stamp. How do you know that Fiverr isn't located in such country? They don't disclose their company name and address on the invoice, on their website, they even have hidden domain whois data.
So this proves that the Fiverr invoice could be invalid.
If you have a corporation and a business Paypal account, you would better buy services from Fiverr using your personal Paypal account, and not your business Paypal account.