Nobody knows. People make assumptions and or project HHN as the be all, end all for the Comcast Corp and wrongly extrapolate from that.
It could be Epic related, it could be that Comcast announces their 2Q earnings next week and the Theme Park Division already gets to say they sold out 3 whole category of premium experience tickets in a matter of hours and want to mention that the "bump" of an IP Scare Zone and Monsters house is yet to come, or they wanted the podcasts to be ready for these last announcements and they weren't ready for whatever reason, or they decided to not force an IP Zone (or house or show) into a "dump" at the end of the week that might not be picked up by news outlets so they want to announce the rest of the zones, Monster house and Nightmare Fuel next week, etc.
Nobody TRUELY knows...and while everybody will surely ridicule them for announcing two zones in 2 days and then going radio silent and not delivering on a "promise" they feel was implied, tickets are selling out so they apparently know what they're doing and the announcements will come soon enough.