This problems occurs from time to time, but I consider it very serious because it can unknowingly lead to content being overwritten in a sheet.
What happen is that you will press CTRL + F to activate the search box. Then you press CTRL + V to paste the value to search for. When the bug occurs, the paste will actually occur in the active cell, overwriting its contents. Even if you manually select the searchbox to guarantee it has focus this will occur.
It's hard to reproduce for me, but it happens too often not to be a bother.
Operating System: Mac OS X
Version: 22.214.171.124 release
*** This bug has been marked as a duplicate of bug 49853 ***