I think I found the problem. In a previous update (I think the December one) DT Reg lost all memory of the "show" field inside of default settings. All of them became "none". So, when I copied a old event the conditional fields had their "used for this event" settings showing "default". The old default setting was "both" but that was lost in the "upgrade". So, once I reset the values to their old "both" setting, the fields show up.
BTW, now if I could just get back the ability to change the order of fields on the registration page...