Disappearing time signature

please, see the attached project.

Could anyone tell me, why in the bar nr 69 (page nr 12) there is no time signature?

This bar has local open meters. When I delete local open meters, the big time signature appears. But when I make local open meter again, the expected behaviour should be to change big time sgianture into small ones in every staff with global meter. So why the time signature disappears completely and there is no signpost to make it visible?
Bar numbers.dorico.zip (748 KB)

Signposts are hidden in the project, and when I show them, I do see the red X signposts for the open time signatures at bar 69 once I start removing the dashed barlines. The ‘Open style’ property is set to ‘None’, which is why neither the X nor the Penderecki symbol appears.

Thank You, Daniel, for the answear. But I think, I didn’t exspress myself clearly.
Please, look at the bar nr 64. There are two different time signatures: „open (Penderecki style)” and 5/8. Why in the bar nr 69 there is no 7/8 time signature in upper staff, which has global meter? When you add more instrumets lines in this bar, they don’t have 7/8 time signature either. And there is no signpost on the global meter parts.