Lightroom 3.3 update GPU error

iMac Pro with Vega 56 8GB, OSX 10.14.6

After installing the latest update 3.3 I've noticed in settings under GPU the following message: "The graphics processor has encountered an unrecoverable error". Strangely, I don't see any difference in usability. However, I understand that currently the app uses the Metal for displaying photos, but doesn't use the GPU for processing. Is this correct assumption? 

In Photoshop this error doesn't appear, but I am using a slightly older version - 21.1.1

I should also mention that I just had the iMac serviced in an Apple Authorized Service Provider for replacing its display and upgrading the RAM (the procedure for which inludes dissasembling the whole motherboard). So, I am slightly worried whether it's their fault in any way, or the software. I did an Apple hardware test which came back without problems. 

What do you guys think - is it a bug in the software or else? Is someone else experiencing this issue? Google returned exactly 2 results for the exact phrase "The graphics processor has encountered an unrecoverable error", so it appears it's not a common one.