I have seen many complaints about photos in the Develop module looking sharp, while the Library Loupe view looks blurry. The problem is often attributed to the sharpening settings, or how lightroom renders in the two modes, or whether the user is in 1:1 mode, etc. I believe, however, that there is at least one bug that causes this problem.
I use two monitors in my setup, and I usually have the right monitor set in Loupe view. I am attaching two screen captures (one above the other) where I am demonstrating the bug.
Both captures show part of a photo at 1:1 resolution with the Detail adjustments (ie, sharpening and NR) turned off. On the left side of each capture you see the photo in Develop mode (on my left monitor); on the right side of each capture you see the photo in Loupe mode (on my right monitor).
In the top capture, you see that the photo in Develop module (on the left) is sharp, but on the right, the photo in Loupe view, is blurry. I believe that LR did not fully render this view.
The bottom capture is the exact same photo, and all the settings are exactly the same. The only difference is that after taking the top capture, I pressed the right arrow key to go to the next photo, and then the left arrow key to come right back to the original photo. Now you can see that the Loupe view (on the right) is exactly as sharp as the Develop module photo (on the right).
When the Loupe view photo is blurry, it looks just like a photo that is in the middle of rendering. It just seems to get stuck before finishing.
In case it matters, this is a raw photo (Panasonic Lumix DMC-GX7 *.RW2 file), although I have repeated this bug with a jpg file. I am running LR 5.4 with camera raw 8.4. My OS is Windows 7 Pro SP1. My graphics card is an NVIDIA GeForce GTX 460.
Any help would be greatly appreciated. I deleted many photos for being unsharp before I realized this problem. Thanks!!
DId you ever find an answer to this? I've been having the exact same problem for a while now and have been completely stumped...