Edit: Link with images further down in post.

So, we just got an Anycubic Kobra Go, brand new, and we've been working on calibrations and learning everything we need to be able to use the device. This device has been put together for a whole 3-4 days now, and the filament we're using (AnyCubic brand, gray PLA) has been out of its packaging for just as long. I've worked out a lot of kinks already, but I'm having trouble finding any solutions for this specific issue.

Whenever a print reaches a certain layer (well, layers on taller prints), it seems (educated guess based on appearance, I don't really know for sure) to have an issue with that layer just not adhering to the one before it, no matter what is being printed. We see this a lot in some of the smaller things we've tried printing to test the printer, such as small fantasy coins for D&D, but larger prints have the same issue on the same layers. Most sources online for these sorts of issues say its underextrusion or an issue with layers adhering together, so I've tried the solutions in those sources to no avail.

• What we've tried so far:Resolution - We saw this issue worst with 0.1 mm layer height, and it seems better with 0.2 mm but it is still there. It becomes super noticeable once again at settings above 0.2 mm
• Flow - We've adjusted the flow up and down with tests on 90%, 100%, 110%, and 120% with no noticeable differences to this particular problem either way
• Temperature - We're using AnyCubic gray PLA, the box says its printing temperature is anywhere from 190-230℃. We've tested it at 190, 200, 210, and 220 with no noticeable differences to this particular problem either way
• Nozzle - I've cleaned the extruding nozzle and also made sure there is nothing clogging or blocking it or the extruder itself with no change in print quality (except maybe a little less stringing?). We did have a mishap earlier where the nozzle grinded into the bed for a moment, but there doesn't appear to be any actual damage to the nozzle itself after that.
• Filament - I've tried unraveling some of the PLA before test prints, just in case the device was having trouble itself. No effect.
• Guide Screw - I have examined the guide screw to the best of my ability and it appears to be straight as an arrow. I also added additional lube just in case since we didn't use all the included lubricant when we initially assembled the device, but this did not lead to any noticeable differences.
• Print Speed - I've tried speeds as slow as 10mm/s and up to the Kobra Go's "stated maximum" speed of 100mm/s with no difference in whether or not this issue is present

Here is an album with a print where this problem is most noticeable:https://photos.app.goo.gl/iwkhDr9M5YVLy4cN7

I am not above destroying or breaking down the print if someone thinks there might be evidence inside of the print that might help solve this printing issue. I have a few other smaller prints (the aforementioned rpg coins) where this issue is also clearly present, but it's not as noticeable as in this print. If you feel that seeing those can help diagnose an issue, then let me know and I'll share them as well.

For settings, I'm mostly using the default settings given by AnyCubic for the Kobra Go when they instructed how to set up a custom profile for Cura, but with z-hopping enabled.