Thank you for your post.
First, no issue with what you described has been reported. That doesn't mean it isn't an issue! However, from what you describe, this should work, as it is common for users to update the external SQL source and resync.
Were any of the four changed fields the primary key? Also, were these four fields placed next to one another by creation order? Were they of similar field types? Without breaking confidentiality, are you you able to tell me the field types that were affected and the calculations? Do you recall if you verified the auto-enter calculations before the two fields were added? Any other details you can provide may be helpful.
Try creating a new database file and link to a new ESS table. See if you are able to replicate the problem following similar steps and field types. This might help in replicating the issue.
Finally, run a Recover on the file to see if any errors are reported.