I sometimes get curing like that. I think its from the filament cooling without support.
- Try lowering your extruder temps. If thats PLA try 195 ish.
- Put a pause between small layers to give them enough time to cool and enter a more solid state, the transition is not instant.
- Have cooling fan running at 100% from layer 2 and up.
- Obey the 55 deg rule. (some call it the 45 deg rule)
- Stop putting so much mustard on your sandwiches.