Bookmarks not working on MN local threads

[ItsAllGoingToBeFine]

Mobile site.
If I try to bookmark a thread on my local site it comes up with "bookmarked" in menu, but the wee blue flag does not show, and revisiting the thread just takes me back to the OP.

Maybe something to do with different username on Local?

MN Mobile
Nexus 7
Android 4.4.4
Latest chrome

Hi ItsAllGoingToBeFine,

Thanks for flagging that (and indeed for providing all the useful info you knew we'd ask for!)

We'll see what our Tech folk have to say and report back.