When moving a observer with a sticky piston with a 1 or 2 tick pulse, redstone dust directly on the block where the observer outputs doesn't light up, but can power redstone components.+
+
Also note that the F3 debug menu doesn't show up that the dust is being powered.
Thank you for your report!
However, this report is Invalid.
Your game is modified with Optifine. Optifine is a very heavy game modification, and using it will automatically invalidate reports on the bug tracker.
If you can reproduce the issue in a vanilla game environment, please create a new ticket - this is a bug tracker for the game, and not a support website. Just saying you reproduced it without Optifine while still providing all in-game footage from when the modification is installed also invalidates the report.
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