You have a plugin loaded that has latency. It’s the way some plugins are. For example iZotope has a few ‘look ahead’ plugins that do this, as does Waves ‘Breath Control’. It’s the nature of the beast, they process the audio for a brief moment to do their thing, and then let the audio play.
Further, the only time this turns bad is when your DAW can’t sort all of this and you put more demands on it (like loading a plugin like this on an input track). You have to let it do what it does although sometimes (in iZotope) there are latency adjustments that you can make…but all signs point to the idea of using a particular plugin at mixdown only and letting it do it’s thing.