More than 3 downwards facing dispensers in a row sometimes don't place/pickup water properly, when activated at the same time via redstone. (See video attachment.)
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Why is this still unconfirmed?

I tried to reproduce that but for me everything worked just fine.
Did you use a Snapshot?

Thanks for trying. No it's 1.15.2 release. (Singleplayer, no mods at all.)
Note that placing the water works most of the time. Picking it up always fails in some way with the setup shown in the video.
Also note that there must be 4 or more downwards facing dispensers.

Update: I have tested a few things and the bug doesn't depend on chunk borders or the direction of the setup (north to south or west to east). It also doesn't depend on the direction from which the redstone signal comes from.
I can always reproduce this bug with all those possibillities.

Intended behavior, some of your dispensers are being powered via quasi-connectivity diagonally but your setup is not updating the dispensers updates.
Switching the blocks the dust is on to upside-down slabs should allow your contraption to work the way you expected it to.

Thanks that worked but that's very unintuitive. I still don't understand why this is expected or "intended behavior".

Thank you for your report!
We're tracking this issue in MC-108, so this ticket is being resolved and linked as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
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