I have also experienced the Bootloader issue with my Nexus 5X. I contacted Google, who told me that I am out of warranty, and I should contact LG. I am based in Canada, so I contacted LG Canada, and they say that cannot repair the phone as it isn't a 'Canadian' Nexus 5X, it is 'US' Nexus 5X, with a US IMEI. They advised me to contact LG US. LG US will not ship to Canada, and advised me to speak to Google about the incorrect IMEI number.
I contact Google Support again, who admit that they should have sent me a Canadian Nexus-5X, and will 'negotiate' with LG Canada to resolve the situation.
Over 10 cumulative hours on the phone, and 15 days later with no resolve, or time frame for a resolve. Only an email from Google Customer Support Team saying that they are still figuring out the situation and to 'be patient' for longer. Completely unacceptable customer service!
I was also informed that there are other customers in this situation.
At this point, the Google Support Team are not resolving their mistake promptly, and I'm left with no other option but to file a consumer complaint with the Ministry of Government and Consumer Service.
I hope everyone is having more luck with Google Support Team than I am!