day 33 is quite late, but there are oddball autos with long vege phases... they also get mis-packaged or some flaw in breeding cycle etc... should be rare.
i don't know for certain if the autoflower breeding process results in 100% autos or something like "99%" of outcomes. I think it's damn near 100% even if it falls short because it's incredibly rare... probably more likely something got mispackaged or a rogue bit of pollen contaminated the process etc.
if it doesn't start to flower in 7-8 weeks, probably need 12/12 for that plant. As long as you can provide same DLI over 12 hours, it won't hurt yield. All other factors the same, you need 150% of the power for 12 hours compared to 18 hours.