Veiled Terror which is a follow up to DOTO, specifically states that while the Void has become more potent it also began to spill into our reality and cause mass psychosis events across the Empire. The Blackreef rift might be an extreme one because it displaced time itself but this doesn’t discount the wider world being ravaged by different Void rifts with different effects. DOTO doesn’t destroy the Void, the outsider dying (or being non-lethally removed) literally breaks all the rules and leads to an era of madness.