Some problems popped up/out at the last second, so it took us two extra

Some problems popped up/out at the last second, so it took us two extra days to finish the work.

Which prep. fits better in the above and why? Thanks.

Yankee wrote:

I'd only use 'popped up'.  The meaning would be similar to 'came up', but with an added sense of suddenness.  The use of 'popped out' simply doesn't sound idiomatic to me in the context.

Thanks, Amy.

But I still have some doubt.

Does "popped up" also refer to "showed up suddenly?"

Is the reason that "popped out" doesn't do the trick because it refers to "moved out suddenly?"

Thanks, GG.

Roger!