I just remembered that I need to ... (= I still remember it).

[emsr2d2]

I just understood what you're talking about!

There's nothing wrong with that sentence. It would normally be preceded by some sort of exclamation like "Ohhhhhh!" It sounds like you've just had a eureka moment.

 

[Tarheel]

@Marika33 "I just remembered" doesn't mean you still remember. It means you just then recalled what you were trying to remember.

 

[Marika33]

@Marika33 "I just remembered" doesn't mean you still remember. It means you just then recalled what you were trying to remember.

But still it doesn't mean you've forgotten it either.

 

[Skrej]

It means you had forgotten it, but now remember it again.

 

[Tarheel]

But still it doesn't mean you've forgotten it either.

I didn't say it does.

 

[jutfrank]

Can we use "understand" and "remember" to talk about not a state, but an action?

Yes.