Well ive been cutting for a few months and im ready to start bulking (first time ive bulked before). So my question is, is it good/safe to go from 2500c one day then the next day go right up to 3500c?

When you end a cut you are at the easiest point of gaining fat instead of muscle from a surplus. It is best maintain and eat at maintenance for a month or so to make your chance of muscle build of fat storage a little better (obviously given the right nutritional/training program)

One month seems like an excessively long time. What's the mechanism behind this long memory?

And how much extra fat would you gain by transitioning in a few days instead? Unless it also takes a whole month of cutting to lose the extra gained fat, you'd be better off in the long run with a quick transition.

When you are in a cut or deficit for an extended period of time your body adjusts to preserve energy. Your metabolic rate slows, you insulin sensitivity decreases, you decrease your ability to oxidize fat cells, you increase your ability to store fat. The last thing you want to do while your body is in this stage is to start packing on excess calories in effort to gain LBM. Your partioning during this stage is going to be leaned more towards fat increase over muscle increase.

1 month is not a long time to wait. If you have finished a cut it means you like a leaner look and lower body fat, if you want to keep that look work into the bulk slowly, otherwise you are just a yo-yo dieter that will live more at 15-20% rather than 8-12%.

Your explanation didn't really cover why the body would remain in that state for so long. Not saying you're wrong, just interested to know.

Well the point is when those things are decreased/increased it takes time to level out. Unlike what some believe regulating hormone levels, especially leptin and adiponectin take more than a few high re-feeds. If you take a month to work your way back up to maintenance (because this should be done with a little caution itself) and then stay a maintenance, you are going to hit at building LBM at a better time.

Would the same thing apply for bulking to cut? Bulk, then MT for a month, then start cutting.