Screen not working after 1 month of use. (after screen replacement)

I have the following problem:

I've replaced an iPhone 7 with a OEM screen, Everything was working fine and customer was happy with the replacement.

After +/- 1 month of usage, the customer started complaining about touch not working correctly and also the screen was "doing things by itself" like switching screens etc.

So what i did:

I replaced the screen with another screen, but this time I used an Original (pulled) screen.

Also this time, customer happy and everything working perfectly. But after (again) 1 month the screen starts showing the same issues as mentioned above.

Any suggestions what to do?

Thanks!