Using mouse/keyboard sharing software breaks keyboard in-game

[Ailuue]

I use Synergy to move between systems with the same mouse and keyboard. I have never had a problem with this in any game, including FFXI base client, until using Windower. As soon as I leave the window/computer with my mouse and return to the game, the keyboard breaks (in game only). I can use space to start chatting, and type with letters, but I can't press enter. If I don't press space, none of the letter key's in-game functions work, like movement and resting, nor do any other functional keys.

I know this used to be an issue when using a controller, but even with "enable controller" disabled in configuration, this still happens. I've tried running in both windowed and fullscreen. I've tried turning just about every option off/on. Nothing fixes this.

[RubenatorX]

For clarity is the game running on the host computer or the extra? (meaning is it on the one the keyboard is plugged into?)

[Ailuue]

It's running on the host computer.