Wizard on T16. Created vault portal using a ring at the cube. While halfway through it, a seasonal rift appeared. Ignored it and finished the vault. While the countdown to closing the vault was going, teleported back into the vault and entered the seasonal rift. It continued to count down while doing the seasonal rift. When done, the seasonal rift continued but the return to the vault didn’t work. That seems reasonable.
Teleported back to town. Then tried to create a new vault portal using a puzzle ring. This time I received the “item will be destroyed warning” indicating it was about to work, but then the action failed. So even though there wasn’t an active vault, the seasonal rift seemed to be blocking it from another creation.
Closed the game and started a new one. This time the vault did create via the cube.
TL;DR, the seasonal rift is blocking vault creation under specific circumstances. Not substantial, but could indicate other gameplay portal issues.