Why did my 5g Antenna melt?

Last night, I believe my phone took in some water. This morning I received a warning message that Face ID wasn't working, and I lost all cellular connection. In fact when I took out my sim card it looked warped so I went to my provider and received a replacement. This didn't solve the issue so I decided to tear into the phone and look for water damage. After essentially removing every component I peeled away the sticker covering the 5g Antenna and found the connector was melted and charred. Why would this happen and is it even worth it to fix?