[Boris_yo]

Hello.

I noticed when I connect charging cable to my device and then try to tap and hold to perform some action it does not let me tap for long and something releases my tap. For example when tapping and holding to drag icon. It would deregister tap suddenly and I won't be able to perform action. It also registers taps twice because after dragging fails and it happens to be on top of app icon, it would tap while dragging and I would accidentally launch application.

Screen behaves in a weird way too when typing. I would tap on certain key and it would register different key, but one that is in close proximity. Using swype action is impossible because while dragging, something would deregister the tap and tap again on a different key.

All the above happens as long as I touch the screen and while charging cable is connected. Screen acts normally when I don't touch it while device is being charged.

Thanks.

[B. Diddy]

That might suggest a shielding problem -- while the phone is charging, the electromagnetic field generated by the current might be causing the screen to malfunction. Does this happen with other cables?

[Boris_yo]

I do not have other cables to test with.
Should I order one for testing?
If so, should I order from China on AliExpress? There's Anker, Xiaomi brands.
Or I should order original Samsung cable?

[B. Diddy]

You can get any USB-C cable -- no need to spend a lot of money on it.

[Boris_yo]

I had USB to Micro USB cable. Since A5 2017 is USB-C I used included Micro USB to USB-C Samsung branded adapter. I connected both cable and adapter together to smartphone and I still experience same erratic behavior.

Should I still order USB-C cable?

[B. Diddy]

Are you saying you have a separate cable with USB-C, or do you only have one cable that can connect to the phone's USB-C port? The point is to try a different cable that connects to the phone (in case there's a shielding problem with the one you have now).

[Boris_yo]

I only have one cable that can connect directly to the phone's USB-C port and it's the original Samsung cable.

[B. Diddy]

Wouldn't hurt to get an extra USB-C cable as a backup. They're not very expensive.

[Mooncatt]

I'm also with trying the new USB cable. I've had them go bad before and cause this exact problem. It is often usually followed by slow/inconsistent charging as it continues to break down internally (they do wear out over time). If that doesn't work, then to go to another location (friend's house, public space, etc) and try it. This would let us know if it's potentially a quirk with your home's electrical system.

If it's winter where you are, low humidity can also cause touch issues. The same could be true if living in other dry areas.

If neither of those work, it could be a hardware fault within the phone, in which case it could be anything. A damaged component from a drop, botched repair job, worn connections, etc.