I Have the same issue. But I didn't understand if you solve the problem by using Restart small plugin or other completely different solution.
Yeah so what I ended up doing was using Restart's plugin and changing some of the scripts a bit so it kinda emulates the Yanfly plugin, but I think what I came up with is pretty sloppy.

So I have the enemy event move at random and then have the following scripts after
if (this.distanceToPoint($gamePlayer.x,$gamePlayer.y)<5){this.requestBalloon(11)};
^This script makes it so a balloon shows up over the enemy event when the player is near, replace the 11 with the number for whatever balloon you're using, I have it set to that number because I'm using a custom one I added.
if (this.distanceToPoint($gamePlayer.x,$gamePlayer.y)<5){AudioManager.playSe({ name: "AlertSound", volume: 50, pitch: 100});}
^And similarly this one plays a sound when the player is near the enemy, replace "AlertSound" with whatever sound you're using and the numbers after volume and pitch can be what you want as well.
if (this.distanceToPoint($gamePlayer.x,$gamePlayer.y)<5){this.step_toward(0);}
^This is just the script that's already been posted before that makes the enemy walk towards the player when they are near, I copy/pasted it like 20 times so that the enemy keeps following the player for a bit after the trigger without constantly having the balloon appear and the sound playing, and then after about a few seconds the enemy will go back to moving around randomly.
Again, this is the sloppy workaround I did using Restart's plugin and wrestling with the scripts to get the enemy events to act similarly to the Yanfly Event Chase Plugin.