This makes sense, given the coronavirus pandemic. Last week, Google told its North American employees to work from home. As more companies order their staff to do the same, business as usual is going to be disrupted. Delays like these may become more common as the outbreak continues.
Previously, Google told developers to plan for app reviews to take at least three days, and up to seven days or more in exceptional cases. We have clearly entered the territory of exceptional cases.
To make things a bit more confusing, as Android Police notes, it’s not always clear which app updates will trigger a manual review. Updates to apps aimed at children typically trigger a manual review, but sometimes apps in seemingly benign categories are flagged too. Later this year, the company is scheduled to begin reviewing apps that request background location info.