This is the third time that I know of that someone has reported this exact bug. I suggest you file an official bug report with Adobe. Lightroom Classic CC | Photoshop Family Customer Community
Here is one other report of this same bug: Artifacts when exporting images
I have already checked all the other threads on the issue and they did not contain anything that helped on our side. I will leave an official bug report with Adobe(I thought I was at the right place )
Here is some more info on my system specs that weren't included in my original post
Windows 10 - Business Edition 64-bit v.10.0.17763
Lightroom CC Classic 64-bits v.8.0 Build 1193777
Intel i7-7700 3.6ghz processor
HD Graphics 630 (184.108.40.20686)
I’ve been getting the same thing in Lightroom CC in my iPhone X, also for about the last couple of months (since the last update?) found this thread searching for an answer. The red And blue recangles don’t show up at all on the same photos in Lightroom on my iPad or MacBook, only the iPhone. Sometimes they go away when I browse to different photos and come back, sometimes they only appear at certain zoom levels, once in a while they move to a different part of the photo, and sometimes they just don’t go away. It also seems like they first appear when I start to edit a photo in the app, specifically enter the crop tool, but I’ll need to keep an eye on this to confirm. It also only happens with photos I’ve imported, I haven’t noticed it at all on photos I’ve taken with the app’s Camera. Since it appears to be only in the display on my phone and not in the files I’ve tried removing/re-downloading affected photos, which didn’t help at all, and just this morning I deleted and re-installed the app - which seems to have cleared the previously affected photos but they still pop up randomly on others.
I am also experiencing this event randomly. I shot with a Canon 5D MIV and expired the images directly to my Android device. I'm not getting the same artifact on the iPad when I look at the same image. It also does not show up on the original image in Google photos. It looks like it is only present in the app, when I exported it to the phone's gallery it wasn't there. It is a huge distraction on the app though
I’m experiencing exactly the same thing as everyone has said above. It’s totally random.
Adobe has acknowledged this bug -- see this bug report: Lightroom Classic: Red and blue artifacts randomly appear on previews and exported photos | Photoshop Family Customer Co… . Please add details of your issue to the bug report, including the first ten lines of the menu command Help > System Info. Be sure to click Me Too and Follow. That will make it a little more likely Adobe will prioritize a fix, and you'll be notified when the bug's status changes.