When ice tray starts to fill, water sprays from supply line in back

A couple of weeks ago, I noticed something sounded "funny" when the ice maker would fill. Then, I was home and it sounded even "funnier". I inspected to find water on the floor, and when I pulled the fridge out, I noticed the supply line to the ice maker was dripping from the top. When water would go in to fill the ice maker, it would instead spray out all over the walls and floor.

My first thought was that maybe the line was bad, but upon inspection, it seemed perfectly fine. After doing some research, I thought maybe it was a faulty water inlet valve, so I performed the recommended test (turn the water off, drain the line, reconnect the line, turn the water on, but ice maker off and see if the water moved up the line - if so, it would indicate water weeping through the line even when the ice maker is not "asking" for it). The water did seem to be going up the line even with the ice maker turned off, so I ordered the water inlet valve and replaced it only to have the exact same problem the first time the water moved to fill the ice tray.

I am not finding any info. online that tells me what the problem could be and I’m trying to avoid taking the whole freezer apart unless I’m sure it’s necessary. I’d love any help on what to check next. I’m not getting any other symptoms that are helping me diagnose the problem. I think ice production may have been decreasing before I discovered the problem originally, but I’m not sure. And now I cannot leave the line turned on to see if the ice maker would still produce any ice or my walls and floor boards would be ruined! Thanks in advance for your help!