Find and Replace hogging the CPU

This is more out of curiosity than a real question; I noticed that the Find and Replace feature works correctly for the first few occurrences, but about a dozen replacement in, it starts hitting the CPU at 100% and it slows down everything, each replacement taking more and more time.

For example; I’m replacing straight apostrophes ' with the curly ’ version and there’s about 100 hits in the list across 5 pages in my project. The first dozen “replace” I did were quite fast, but after that, it took 1 second, then 2 seconds, then more and more time. At about the 25th replacements, it took a good 10 seconds to replace with the CPU staying at 100% usage during that 10 seconds. It kept taking even more time for each following replacement I did, while still hitting the CPU at 100%.

Closing the Find and Replace window, reopening it again and doing a new search doesn't fix the problem, it's still super slow. I also tried doing it page per page (instead of doing it course-wide), same result.

Any idea why it’s doing that?

Thanks!