This has been discussed before, but in summary: for technical reasons the Scirra Arcade can only accept submissions from one version of C2. This is a problem and we want to fix it but it's technically complicated and will have to stay like this for the time being unfortunately. Either we set that to the last stable release and beta testers can't submit games, or we set it to the last beta release and stable users need to upgrade to a beta release to submit. The latter is how we prefer to do it, so we can get games using the latest features on the Arcade.
Unfortunately this does make it difficult to submit when a beta release is dud (like r96), but this should only happen irregularly, and with approximately weekly updates you should only have a few days wait then you can submit again.
Hope that helps explain the situation!