Edit: I remember having read a discussion here on the LL forums. A user had difficulties to open a heavily modified file in Photoshop. He had 150 or more dust spots cleaned in LR and PS couldn't open the TIFF file unless he used "Minimize Metadata" in the export panel. Not sure if it's relevant.
Interesting. I had a similar experience but more with the loss of speed in LR. I had a bunch of images, 100 or so, that were taken at the end of a dry dusty trip when i had no way to clean the sensor apart from a turbo blower. Punta Arenas, Patagonia lacks some basic camera gear!
On import, i had roughly 100 spot removals. The moment i had finished one image with this tool, the whole LR just ground to a hault. The more images i applied this too the slower it got. I had to restart LR and close the tool, which marginally improved. Now, specifically if i am in this folder, LR performs drunk.