Error invoking 'python_execute' on channel 3 [ALE with Merlin]

## Information

**VIM version**

NVIM v0.6.1
Build type: Release

Arch linux

## What went wrong
I've installed Merlin and configured everything properly, Merlin is working properly on its own as well as with Syntastic. When I use Merlin with ALE, everything ostensibly works perfectly, except for when I close a file I get this error message:

Error detected while processing function 80_NeoVimCallback[29]..4[1]..78_ExitCallback[28]..77_HandleExit[24]..ale_linters#ocaml#merlin#Handle[1]..merlin#ErrorLocList[8]..provider#python3#Call:
line 18:
Error invoking 'python_execute' on channel 3 (python3-script-host):^@Invalid channel: 3%

## Reproducing the bug
Open and close an OCaml file with merlin installed.

### :ALEInfo
in ALEInfo everything is seemingly fine as well:
Command History:
(executable check - success) ocamlmerlin
(finished - exit code 0) ['/bin/zsh', '-c', 'true < ''/tmp/nvimEy5QVd/1/touch.ml''']
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