One item not mentioned but I enjoy...
In "Counterclock" they are near the Beta Niobe supernova, the star that blowed up in TOS "All Our Yesterdays.
In "AOY" the crew encounters the Atavachron, which is a fully functional time machine. In "Counterclock" the crew enters a universe where time flows backwards.
As if being around Beta Niobe and Sarpeidon in both eps leads to strange time-related hijinks. Something wacky going on in that system? Something that made the Atavachron able to exist?