Wildly Inaccurate print times

Just noticed, my FormLabs 2 print times are suddenly way off! About 50%, so the screen will be reporting < 1 minute but still with hundreds of layers to go. Prints are fine, but I have to wait another 3 hours to see them! Latest software, although I don’t think the printer has updated itself for a little while. Anything obvious I have missed? Prints are just fine, Grey V4, usually 0.05 mm or 0.025 mm layer thickness.