"Active" here does not mean "has power flow". It means that the instruction itself must be scanned by the engine every scan until it has completed. What that means is that it can't be in a stage that you jump out of pre-maturely (because disabled stages are NOT scanned), or in a program code-block that has been EXITed pre-maturely (because EXITed programs are also not scanned).
The edge bit is for firing the instruction, but the instruction remains active as long as it takes to completely execute that instruction asynchronously across multiple scans, so the stage or code-block it is executing in must remain active.