Yes, when it gets to 100%, the actions shown will be taken, that is to enable Alarm and Block on that violation.
Staging is not relevant here (failed to convert character) because staging is not a property of Violations -- it applies to URLs, Attack Signatures, parameters etc, so that is not affected.
A way to interpret that particular learning suggestion is that the system is seeing traffic that isn't triggering that violation, so it is 50% sure that it is safe to enable blocking and alarming (more so if you look at the event logs and you don't see any requests that are flagged with this violation).