Minecraft server has huge delay in commands?

Minecraft server has huge delay in commands? - 1

Added (1). The server itself is not laggy, however there's a huge delay in commands, what I mean is, if me or anyone else does /gamemode 1 it takes about a minute to actually do the commands and for it to show up in the console.

Added (2). The server itself does not lag, everything seems fine, fps stays high for everyone on the server, it's just that every once in a while (especially when logging in) if you try to do a command, it takes a while for the console to show it, and for the command to actually be executed.

Added (3). I don't think it is bad internet either, I have ethernet, fibre optic.

Added (4). By the way I have ran many servers before and this is only happening on 1.8.

Probably due to lag or bad internet. Check your internet and try again. Hope that helps!

Probably the internet

That means your ping is too high.
Your internet communicating to the server is taking a lot of time.
Try using a server in your country or near by

Low ping-lowest delay
High ping-longer delay