When I compare two oracle databases then any sql developer version after the one just managed apparently (incorrectly) make a
script with DROP sometable followoed by a CREATE sometable
The old version properly makes ALTER sometable...
So be aware to always check the result by hand. It contains bugs...
What is the bug?
Please tell us which version you are running now.
Tell us what the two tables' DDL are, and then share the DROP/CREATE and ALTER delta scripts that you are seeing.
We recommend you always test the results before deploying to your systems.