It has happened to me previously also using BOTH namecheap/godaddy, back then I just shrugged it off, but this time it really pissed me off...
So I guess the best bet is to check for domains on the ACTUAL ENTITY PROVIDER who provides domain names to resellers, such as:
https://www.verisign.com/en_US/domain-names/domain-name-sear...
Plus their brainstorming feature is one of the best out there IMO.