The 'Carry On' mod allows you to pick up items and put them back down.
Github: https://github.com/Tschipp/CarryOn

This includes the Pixelmon PC, Cloning Machine, Healer, etc...

Issues:
* While 'carrying' an item, if you are attacked by a wild Pokemon, it glitches the client, requiring a client restart.
* If you pick up a PC, and place it down in a different location, it leaves behind a ghost PC (possibly due to it being 2 blocks tall). You can then break both PC's with a pickaxe, thus duping the original.
* When you pick up a cloning machine, it leaves behind a LOT of ghost blocks.

More issues caused by the interaction between these two mods is that Pokemon and NPCs can be picked up and carried.

Before v7.0.0, there was no problem with this. Since the latest updates to Pixelmon, when you put the Pokemon back down, it will faint.

Also, when picking up a Trainer/NPC, it's data can be corrupted.

One workaround 'fix' for all these issues is to simply blacklist all Pixelmon items in the Carry On mod, but adding the following to the Carry On blacklist in the config files:

pixelmon:*

Thanks for the report. I'm unsure whether this is anything we can fix on our end, but will pass it along anyways. Keep an eye on the ticket status!

From what I understand so far, this is likely a bad interaction between the Carry On mod and Pixelmon. A lot of Pokémon-related things changed in 7.0, and they now have their own way of working.

While this should prevent a lot of the old issues (dupe bugs especially), it most likely also broke Carry On. It may be worth bringing this to the attention of that mod's dev/team, but I don't think we can do much about it on our end. Sorry!