AutoSSL Assigning LetsEncrypt cert without it being Installed

Hey everyone, I'll try and explain this as concisely as I can but the entire issue seems very odd to me and I can't find a common linkage. Overnight, we received an email that some subdomains from a newly launched site failed to receive their Cpanel auto SSL Certs claiming that it could not reach the validation file on a server that has nothing to do with us. [removed - please attach images directly to the thread] In Cpanel, it shows that the certs were in fact issued by Cpanel for 3 of the domains successfully. [removed - please attach images directly to the thread] I did a bit more digging and went to one of the subdomains (autodiscover) and, to my surprise, it had a certificate already installed. Even stranger, it had a LetsEncrypt certificate installed. LetsEncrypt isn't installed as an autoSSL provider on this server at all. And the cert that's installed is for the mail subdomain, not autodiscover. [removed - please attach images directly to the thread] Drilling down even deeper I found that the cert sees domain is a subdomain of site that we have no association with. domain.tld [removed - please attach images directly to the thread] I went to domain.tld and viewed their cert. It looks like they are using cpanel/letsencrypt to secure that domain and several others. I know this is a bit rambly, but I can't make sense of this situation and it's kind of concerning. Could anyone please shed some light as to what's going on to put my mind at ease? Thanks!