I'd say, 99% of freewheels out there have a wobble of some sort, in some degree, when freewheeling.
Pretty much, expected/normal.
I never experienced any sort of skipping from this wobble as chains are quite flexible by nature, so as to should not get affected, within the production tolerances that FW manufacturers leave on their product, short of the FW being totally non- functional.
I would suspect, other things with the drivetrain is causing it, like a worn chain stretch out of its service tolerance or stiff links on your chain or damaged teeth on the FW cogs...... maybe even a chain that is too wide for the FW cog spacing.