It appears that search is stripping extra spaces from search phrases, and then of course, failing to find matches where extra spaces exist in the document.
If I type:
0 "Extra spaces"
1 "Extra spaces"
2 "Extra spaces"
3 "Extra spaces"
And then copy and paste any of the “Extra spaces” phrases (with quotes) into the search window, I expect the exact phrase I copied to be the one phrase found.
Instead, the first phrase (with no extra spaces), and only the first phrase, is always found. Whether I put one space or 20 spaces between words, only matching phrases with a single space between each word are found.
I have verified in the Windows 10 desktop app version 1.4.5, and in the Chrome browser. My installation’s are unmodified (no scripts).
Edit: I just noticed that, as displayed, the extra spaces I entered appear to have been stripped from the post. Ironic. In case it isn’t clear, in my test data there is one extra space (2 spaces total) between the words “Extra” and “spaces” on the line beginning with the number 1, and so on.