How would you say it another way?
I wonder about you sometimes.

Does it mean;

I'm surprised at you sometimes.

Question

How would you say it another way?
I wonder about you sometimes.

Does it mean;

I'm surprised at you sometimes.

Answer

Depends on context.

If you're done something stupid or weird somebody may say "I wonder about you sometimes..." which means, sometimes I wonder what is going on with you/why you do weird things/what's wrong with you.

Said on it's own, it might mean somebody misses you or thinks about you often, e.g. "I wonder sometimes how you're doing or where you've been"