Dell dock with multi-monitor setup

Hi all,

I have a strange problem with using multi-monitor setup with Dell dock. Most of the times it works OK, but sometimes if I disconnect dock while computer is running and return it back, I get no display data (all monitors go to power save). When I analyzed this I figured out that I have too many monitors listed and sometimes it just selects some non-existent monitors.
To solve this, usually it is enough to click try automatically (Alt+T, blindly, because I do not have picture) which setups clone on all monitors then to configure monitors properly from KDE setup.

I will attach output of xrandr command (in working condition). You may notice that somehow I got as high as DP1-2-8.. But I only have 2 DP monitors. eDP1 is monitor of the laptop itself.
Where these list is being kept, so I may reset it? I was expecting some udev persistent rules, but didn't find any.

Any help is appreciated, thanks!

Code:Screen 0: minimum 8 x 8, current 5120 x 1440, maximum 32767 x 32767
eDP1 connected (normal left inverted right x axis y axis)
3840x2160 60.00 + 59.97
3200x1800 59.96 60.00 59.94
2880x1620 60.00 59.96 59.97
2560x1600 59.99 59.97
2560x1440 59.96 60.00 59.95
2048x1536 60.00
1920x1440 60.00
1856x1392 60.01
1792x1344 60.01
2048x1152 60.00 59.90 59.91
1920x1200 59.88 59.95
1920x1080 59.96 60.00 59.93
1600x1200 60.00
1680x1050 59.95 59.88
1400x1050 59.98
1600x900 60.00 59.95 59.82
1280x1024 60.02
1400x900 59.96 59.88
1280x960 60.00
1368x768 60.00 59.88 59.85
1280x800 59.81 59.91
1280x720 59.86 60.00 59.74
1024x768 60.00
1024x576 60.00 59.90 59.82
960x540 60.00 59.63 59.82
800x600 60.32 56.25
864x486 60.00 59.92 59.57
640x480 59.94
720x405 59.51 60.00 58.99
640x360 59.84 59.32 60.00
DP1 disconnected (normal left inverted right x axis y axis)
DP1-1 disconnected (normal left inverted right x axis y axis)
DP1-2 disconnected (normal left inverted right x axis y axis)
DP1-2-1 disconnected (normal left inverted right x axis y axis)
DP1-2-8 connected 2560x1440+2560+0 (normal left inverted right x axis y axis) 600mm x 340mm
2560x1440 59.95*+
2048x1080 60.00 24.00
1920x1080 60.00 50.00 59.94
1600x1200 60.00
1280x1024 75.02 60.02
1152x864 75.00
1280x720 60.00 50.00 59.94
1024x768 75.03 60.00
800x600 75.00 60.32
720x576 50.00
720x480 60.00 59.94
640x480 75.00 60.00 59.94
720x400 70.08
DP1-3 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP2-1 disconnected (normal left inverted right x axis y axis)
DP2-2 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
2560x1440 59.95*+
2048x1080 60.00 24.00
1920x1080 60.00 50.00 59.94
1600x1200 60.00
1280x1024 75.02 60.02
1152x864 75.00
1280x720 60.00 50.00 59.94
1024x768 75.03 60.00
800x600 75.00 60.32
720x576 50.00
720x480 60.00 59.94
640x480 75.00 60.00 59.94
720x400 70.08
DP2-3 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)