I tried looking for a thread on this, sorry if this had been discussed already.
When using a chisel and holding down the action button, the first two hits are one speed and subsequent hits are markedly faster. No other mechanic works like this, do we have an explanation for why?
When they added guild buffs we had the problem that with the now increased block placement speed you were no longer able to place single blocks. That’s why this feature was added. If I remember correctly you can disable it in the settings.