Can't interact what so ever with command blocks

Alright so, the oddest thing happened:
I was working with command blocks, then i logged off, logged back on the next day, got de-oped, then oped again. Then command blocks broke for me and only me:
There was no break or place sound for when I broke/placed them
My arm didn't move while placing them, they just 'appeared'
I could not open the GUI when right clicking them.
I could hear the sounds when someone else did it, and they could edit them.
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Op perms is level 4.
command blocks are enabled.
online_mode is true.
I was oped.
I was in creative.
Antibuild isn't on here nor is world guard, as far as I know, just essentials and worldedit is on the server.

Anyone got any help?

 

Were you lagging? No sound and arm not moving are often signs of bad lag and will fix in a minute with late sounds and late GUI openings?

Can you interact with other blocks like that (Crafting Bench, Furnace,)?

Does the Console say anything when you try that is not ordinary?