"Not in a mode" error from VimuxRunCommand in scroll mode

[tradiff]

I get the "not in a mode" error when using VimuxRunCommand while the Vimux pane is in scroll mode.

Repro Steps (confirmed on default tmux config):

• In neovim, run :VimuxOpenRunner
• in the new VImux pane run ls ~ to get some output
• in the new Vimux pane, enter copy mode (C-b PgUp in default keybindings)
• In neovim, run :VimuxRunCommand("ls")

The following error is displayed in neovim:

Error detected while processing function VimuxRunCommand[10]..VimuxSendKeys[2]..VimuxTmux[8]..function VimuxRunCommand[10]..VimuxSendKeys[2]..VimuxTmux:
line    8:
E605: Exception not caught: Tmux command failed with message:not in a mode

I get the same error when calling the tmux cli directly:

> tmux send-keys -t 2 q C-u
not in a mode   

This seems to be related to q C-u being sent together. If I run them as two separate commands, there is no error:

> tmux send-keys -t 2 q
> tmux send-keys -t 2 C-u

I realize splitting into separate commands might not be compatible with VimuxResetSequence being configured as a single string.

Here are some versions.

> tmux -V
tmux 3.4

> nvim -v
NVIM v0.10.1
Build type: RelWithDebInfo
LuaJIT 2.1.1707061634
Run "nvim -V1 -v" for more info

> alacritty --version
alacritty 0.13.2

vimux: (I don't know how to get neovim to tell me this, but it should be the latest master)

I'm happy to answer any other questions or make a screen recording if needed.