Learning Suggestions Removed from Manual Traffic Learning due to Learning Incident Limits

I'm quite new to the ASM module and had no idea there was a limit on the number of learning incidents that ASM can store. I had several learning suggestions in the manual traffic learning that suddenly disappeared and found out that they were removed due to the 100,000 learning incident limit. I'm not sure what exactly happened to these learning suggestions. Were they accepted, clear or disabled? Has anyone experienced this?

I recall that one of the learning suggestions that was removed was one of the HTTP protocol violations - header name with no header value. It is currently disabled, but when I try to enable it then save and apply the policy, it somehow disables itself and I can't figure out why it won't allow me to enable it.

Does anyone have any best practices how to they have dealt with this limitation? I can't see how this is feasible if multiple policies are running.