LG 27UD88 - MacBook Pro (13-inch) loses settings after being put to sleep

I asked about that once already, and I was given a solution which I thought worked (resetting NVRAM). Unfortunately, I was wrong. NVRAM Reset didn't solve the problem, and I am still experiencing this annoying issue. So I am asking again, as the previous topic has been marked as "solved" and there is no way to "unsolve" it.

Almost every time my computer wakes up from sleep my resolution and screen arrangement settings are lost.

I am using MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports with macOS High Sierra 10.13.2) and LG 27UD88 (27-inch 4K display) connected with USB-C cable provided with the screen.

Please refer to the attached image with System Preferences screenshots:

As you see at the bottom of the picture, my preferred settings are "like 1680x1050" for the built-in display and "like 3840x2160" for external display with arrangement when the external screen is placed above the built-in one and menu bar is set for the smaller screen.

After my computer wakes up from sleep, those settings are lost. Both displays are set to "default for display" resolutions which are "like 1440x900" for the built-in display and 1920x1080 for external display. Screens are also arranged side-by-side. Moreover, external display settings window looks different: instead of those little icons placed on "Larger Text - More Space" scale, I have just a standard list of resolutions.

To restore my settings, I have to restart my computer.

This problem occurs almost whenever my computer goes to sleep (let's say, every second time? - almost always when my MacBook has been put to sleep for a more extended period, like a day or two), also when:

- it was connected to the external display when put to sleep, then woken up - settings are lost;

- it was disconnected from the external display, then put to sleep, then woken up and reconnected to the external display - settings are lost;

- was not connected to the external display since the last restart, then put to sleep, woken up and connected to the external display - settings are lost;

- etc.

I also tried with different resolutions. Same effect.

Is there any fix for that? This problem is very annoying, as whenever it occurs, I have to restart my computer.

I will appreciate any feedback or information about this problem. As I mentioned before, resetting NVRAM didn't fix the issue (I tried three times).