Had same issue, tried all of the above until one method worked:
Downloaded 1.3.5, imported save, suddenly next stage showed properly, saved, exported back to 1.3.6 in browser.
Thinking of it, was playing fine up until yesterday when suddenly the popup/overlay on star chart disappeared, so something wonky in the 1.3.5->1.3.6 process when at that exact point in game.
Ofcs there is a chance bugs can follow with importing back and forth between versions like this so would like proper fix, but worked for now