This (or very similar to it) happened with my OOW iPhone X back in November 2018--I took it in to have the battery replaced (it expanded), they tried to replace it but subsequently told me that they had to give me a replacement (refurb) phone due to tearing the adhesive (or something like that--I don't remember the specifics TBH); they handed me my old phone and told me to wipe the phone (while they watched) before handing me the refurb replacement. $29 (the cost for an OOW iPhone X battery replacement) for a refurbed iPhone X, not bad IMHO.