In the light of this letter, it is likely that Epiphanius was suspended during the course of investigation into his alledged crimes which seem to involve some indecent relations with a certain woman (Gregory's letter 3.36 [2327]).
It seems that Epiphanius was called to Rome, for Gregory to investigate his case personally, or, just possibly, the presbyter fled to Rome to avoid punishment at Sardinia, seeking Gregory's protection.
Dey 2008 argues that xenodochium was a type of a monastic institution whose everyday obligation was the care for the sick. Thus, Martyn's translation of xenodochia as "hostelries" might be misleading.