Although you didn't show the contents of $:/tagged/journal, I assume it contains a $button that sends a "tm-new-tiddler" message to create a new journal tiddler.
If this is the case, then I suspect the problem is due to a subtle yet important aspect of the $button definition.
If you define a button using "inline" actions, like this:
<$button>
label
<$action-sendmessage message="tm-new-tiddler" etc... />
</$button>
then the button's action(s) are parsed when the button is rendered. Thus, if the action(s) calculate the new title based on the current time (i.e., using the <<now>> macro), then that new title will use the time that the button is rendered.
However, there is a different way to invoke a button's action(s), using the actions="""...""" parameter, like this:
<$button actions="""<$action-sendmessage message="tm-new-tiddler" etc... />""">
label
</$button>
or like this:
\define myActions()
<$action-sendmessage message="tm-new-tiddler" etc... />
\end
<$button actions=<<myActions>>
label
</$button>
In this case, the button's actions are parsed when the button is actually pressed. Thus, any use of the <<now>> macro will correctly reflect the time when the button is pressed, not when it was rendered.
Note that the TWCore's NewJournal button ($:/core/ui/Buttons/new-journal) uses the actions="..." method, while the NewJournalHere button ($:/core/ui/Buttons/new-journal-here) uses the "inline" actions method. Thus, NewJournal uses the correct "time of button press" timestamp, while the NewJournalHere button uses the incorrect "time of button rendering" timestamp.
Hopefully, the above info will help you fix your button...
Let me know how it goes.
-e