I was about to give up on a project in which there was 2 months of daily hard work invested because of this.
Ashley It is shown in the Real-time Multiplayer example and the tutorials that "Add Input Client Value Tag" are set BEFORE connecting to the signalling server, but there is no explanation that this is absolutely critical.
I had read every tutorials and followed all multiplayer examples and this information was nowhere to be found.
My Host was receiving peers inputs data completely randomly from one project preview to another without changing anything to any events or actions and it was driving me absolutely crazy. I spent hours trying to debug and figure out what was causing that issue until I finally landed on this post randomly:
https://www.construct.net/en/forum/construct-3/how-do-i-8/multiplayer-input-states-152993
The real-time example should highlight and explain a little the reason why setting this before connecting to the server is mandatory for all data to be transmitted accurately.