Engadget
Stop bringing your phone in the shower: How steam can ruin 'waterproof' phones

Smartphone IP67 and IP68 ratings indicate water resistance, not total waterproofing against steam or humidity. Hot shower steam penetrates charging ports and seals, causing internal condensation and degrading battery health. Heat exposure above 95 degrees Fahrenheit further damages internal adhesives and components, often leading to permanent, non-warranty-covered hardware failure.