Triple click the paragraph beginning "Osobně se přejmenování..." on https://cs.wikipedia.org/wiki/Diskuse_k_Wikipedii:WikiProjekt_Olympi%C3%A1da#%C5%A0ablony_medailist%C3%A9
Observe that the "J" in the next comment is selected:
With the reply tool disabled, this works as expected:
Observed in Chrome on Ubuntu and by another user on Windows, but works fine in Firefox.
Update: Filed upstream: https://bugs.chromium.org/p/chromium/issues/detail?id=1116214