The scheduler is always bound to the web context (which is usually bound to the hostname). In case you are not seeing it and they are still running, then you are very likely looking in the wrong web (context) administrator (e.g. looking in the web admin of www.myapp.com:8888/lucee/admin/web.cfm instead of localhost:8888/lucee/admin/web.cfm or vice versa)
I discovered yesterday that all mine had actually been wiped out after I upgraded Lucee to the latest stable version (5.3.8.189). It seems the tomcat web context had been recreated without copying the previous xml file.
Luckily I have a script which will recreate them instantly, and I’d recommend everyone using Scheduled Tasks do the same. It’s pretty easy using cfschedule.