Take the MBA to a local store (or work) and hook it to another monitor or two, then give it some time to see if the problem happens on another one(s) too. That would narrow in on the problem being MBair vs. monitor. It would be particularly good if you could find a store with a display model of the
very same monitor as then most variables would be identical.
If it doesn't replicate what you are seeing on another monitor(s), something is likely up with the monitor you own. If it does replicate- while it could still be a monitor issue- odds increase that it is the MBair.
A
TechSpot review of this monitor includes this relevant info...
I don't think Mac has any equivalent ClearType utility anymore. Instead, Apple wants us to pay up for oddball "retina" resolutions vs. cost efficient commodity resolutions like 4K.
Narrowing down the variables is often the only way to resolve a tech problem that seems isolated to a single (or perhaps few) user(s). Other things you could try (some of these solely to narrow in on exactly what is driving the issue):
- Pull the plug on the monitor, wait a few minutes, plug it back in and see if a cold (full) reboot perhaps shakes out some bug that snuck into the monitor... perhaps in a power blink.
- Pull the video plug, let Mac adapt to using its own screen, then plug video plug back in so it can do a fresh "handshake" connection with this monitor.
- Is "auto-update" turned on on the monitor and it perhaps did a software update just ahead of this starting?
- Cable: easy enough to try a different cable, so try it. If you perhaps pinched some pennies on the cable, consider replacing it with one that is high-rated and even a little overkill for the connection, like maybe HDMI 2.1 8K cable or similar.
- If there is more than one input port, try the other port. LG C2 has FOUR HDMI ports. Try the others to rule out a single port issue.
- Going through a hub (Mac to Hub to C2)? Temporarily try a direct connection to rule out the hub.
- Have another Mac or maybe a friend has one? Hook it to this monitor with the very same cable and use it with the monitor for a while to see if this problem shows itself again. If possible, try to run the same app(s) for about the same amount of time that typically triggers the issue. If another Mac doesn't show the problem, you'll know your Mac probably causes the issue.
- Any new technology added within about 50 feet of this monitor, coinciding with the start of the problem? Sometimes other tech can cause interference issues.
- Dust in the ports? Ants?
- Heat? Maybe high demand use or hours of use before things get too warm and perhaps cause this? As the northern hemisphere shifts into late spring and then summer, is the Sun now perhaps hitting the monitor front or back this time of year?
- Some kind of time-based, energy efficiency mode on the monitor that kicks in and uses less power, maybe after a period of apparent inactivity- such as if you are reading a web page or staring at the same code without interacting with the content?
- LG C2 is an OLED monitor... which means it almost certainly has "burn in" avoiding modes. Could one of these be kicking in due to bright elements on the screen being in one spot for too long... like when you just leave the same content in the same place for a good while? On this very topic in that same TechSpot review...
The name of the tech problem diagnostic game is to systematically test variables to figure out exactly what is causing a problem. As is, there are MANY possibilities from software updates (Mac and Monitor) to hardware (cable, possible hub, ports) to environmental (heat, shifting sun, power blink (without a reboot)), to misc (some new purchase in the vicinity causing signal interference, some kind of energy save mode kicking on, etc).
It very well could be a Mac fault, macOS fault, etc but there is plenty of other potential here too. Work through the list and you may discover the cause. If so, you can then focus on alternatives to overcome the issue.