I am not sure if anyone has also faced this problem, but the objectid will suddenly increase with a big number. Does anyone know why? Thanks.
What kind of database is this in? I think the bigger problem is having a Null ObjectID.
You might see a jump like this if you deleted a bunch of records. New features don't then start numbering ObjectID after the last existing value, they start after the last one used, even if it's now deleted. So in your example, if you'd deleted records with ObjectIDs from 236 - 633, the next ObjectID would start at 634, not 236.
This is a general rdbms rule; specific dbs might implement this differently.