Can't paste more than around 30-lines into tmux buffer

[gberenfield]

I can't seem to paste in around 30-40 lines of code into my vimux repl. Anything less works fine.
It could easily be a tmux setting but I can't seem to find anything relevant.

I'm using vimux as a tslime replacement and followed the mappings in the docs.

tmux: 1.6 (via homebrew)
vim: 7.3.646 (sourcecode compiled)

Wishlist: If there was a command to pass the entire file/buffer to the vimux buffer

Brilliant plugin!
Thanks
Greg