Star System warp is something that they never seem that consistent on. In BOBW they slow down,
But they do stay FTL all the way to the intercept at Earth.
With untested engines.
in TMP they say they have to risk going to warp to get to V'Ger quicker,
The wormhole accident resulted from the unbalanced engines.
and in the episode where Bashir is revealed as a Changeling, Dax seems distraught that Kira suggests going to warp as they could fly into the star.
I think that was "By Inferno's Light". Dax did seem to balk at that although Kira didn't think it would be a problem. However, they've had runabouts at warp in the system as well so this might be specific to the Defiant.
DAX: Its shields are holding.
KIRA: How can that be?
DAX: Looks like someone's been doing some modifications to the Yukon. I'm also picking up large amounts of trilithium, tekasite, and protomatter on board.
KIRA: A bomb. If it explodes inside the sun
DAX: It could trigger a supernova. Wipe out the entire fleet, the station
KIRA: And Bajor. We have to use the tractor beams.
DAX: We're too far away.
KIRA: Wanna bet? Take us to warp.
DAX: Inside a solar system?