Missing piece on stage 7 of event

[Rhyshan]

as title says also refreshing and clearing cookies and re-logging have not fixed the issue

[Hastur]

Presumably you also cleared your browser cache or otherwise deleted all site data?  (Not just clicking "refresh" & removing more than cookies.)

As an absolute last resort, you might want to try to move one of your already-placed pieces.  That will, of course, cost you 2 moves... but it may be better than waiting when your moves max out.  🤞

[Hastur]

When I first read the OP, I noticed the topic said Stage 7 but the progress bar appeared to show Stage 8.  I figured maybe a typo- it didn't change my answer.

However, for what it's worth, I experienced the same bug on the same stage (Stage 7 for sure!).  I had two open puzzle sections & two available pieces- top right & top left corners.  The upper-left corner piece "disappeared" from the puzzle after I placed it but did not return to the available moves section (it was gone from both).  So I placed the upper-right piece (still available) and it snapped into place; still an open upper-left corner & empty available moves.  No reward, no completion, no new puzzle.

I saved, logged out, logged in, waited 15-20 minutes for the game to load & get to the event.  Still open corner & no pieces available.  BUT one of the previously-placed pieces from YESTERDAY in the top row center was suddenly wrong!

I dragged that "wrong" piece to the empty corner twice- the 2nd time, it snapped into place, I got the 600 kinkpoint award popup, saw a new puzzle BUT also saw my progress bar go all the way to the top of the NEXT level (450 affection).  Now very similar to the screenshot above!  (I don't think I was charged any extra moves but, due to the timer/available moves bugs I have no clue.)

I verified my kinkpoints immediately and saw that the rewards were there.

I saved, logged out, logged in, waited another 15-20 minutes to get back in game & everything related to the event looked as it should... including my progress bar being at the bottom of the new stage (rather than the top).

I have no idea if this will be helpful to the OP or developers.  Sorry for no screenshots but there was no way I was going to waste more time on something I didn't know would work on top of the godawful lag.