iPhone Freezing 4 to 5 times per day

Installed an after market screen on a customers phone.

They told me their phone had been dropped in water, I saw a little corrosion on one of the connections. (not the main ones, the home button one)

Everything seemed to work fine but his phone is freezing 5 to 6 times a day. He cracked his screen again. This time I put on an original and it didn’t appear to fix the problem.

This morning he messaged me saying when he “pushes his screen” in, the freezing goes away. He also told me that when it’s fully charged, it doesn’t appear to freeze ever.

Is there anyone who has experienced a similar issue that might be able to give me some advice?

Thanks!