Dual monitor flickering: the secondary monitor does the flicker

I am experiencing flickering with my dual monitor setup. The nature of the flicker is "on/off", i.e. the screen gets completely black for a split second (sometimes a few seconds) and it goes back on. Sometimes it happens when I am not doing anything on that monitor, and sometimes it seems like it is triggered when pixels change on the monitor (opening something, or even just moving the mouse cursor)

I have a dual monitor set up at work with my MacBook Pro 13" 2017 (two thunderbolt 3 ports).

I am using the following to connect these monitors to my Mac:

• BenQ BL2780T monitor
• AOC I2475PXQU
• Kensingon S4600P docking station
• Belkin HDMI-USB-C adapter

The docking station connects to the MacBook via a thunderbolt 3 cable. The AOC monitor is connected directly to the docking with DisplayPort. The BenQ is then connected to the remaining Thunderbolt 3 port on my Mac via a HDMI-USB-C adapter. The docking station provides power to the Mac.

It seems random which monitor flickers; sometime it is the BenQ, other times it is the AOC. Also, it is random which port is involved in the flicker. However, I only see flickering when two monitors are connected at once.

I have also used a Satechi slim multiport (as a very simple docking station), and I see the same flickering behavior. I have tried different cables, and the issue persists.

I have also tried another AOC (same model) monitor together with the BenQ, and it still flickers.

I am going to try another MacBook Pro (same model) this week, and will report back.

Is this a software issue with High Sierra? Are the two monitors "incompatible" for some reason? I see no reason why the flickering happens. I really hope someone can help me out. It seems similar issues are common, but I have not yet found a common explanation to fix these things. Needless to say, I have tried the standard things, like various resets etc.