1. Is the issue only happening for Report Definition rules or other rules as well?
2. Is the issue happening only in DEV environment or other environments as well?
3. Do you know if any change was made after which this issue started happening? (for example, installing a hotfix or any other change to system)
I understand that you wanted to get rid of the problem and so truncated cache tables. But in general, it is not a good idea to willy nilly truncate cache tables, because once you do that, we lose the evidence of what happened that may have triggered the problem and try to address it. We can only attempt to do damage control after that as opposed to understand the root cause of the issue.