The bug happens when exiting the world and loading the world again.

Basically, before exiting the world, the barrel can receive a redstone signal and give and output (just like a regular block).

But - if you will exit the world and then relogging -> the barrel stop working which means that redstone don't pass through it at that point!

See the video if it wasn't clear. Ask me anything you want.

By PHO: Confirmed to be affecting 1.14.0 (iOS).

Barrels behaves like a solid opaque block until you relog. That is,

• Strongly powered Barrels can power adjacent redstone dust.
• Weakly powered Barrels can activate adjacent redstone components.
• Redstone torches attached to a side of a Barrel can negate its output based on the powered state of the Barrel.
• Repeaters can receive power from weakly powered Barrels.

But once you relog, Barrels lose all of these properties and starts behaving just like Glass blocks. Breaking and re-placing them will recover their initial functionalities.