Error 2601: Cannot insert duplicate key row in object

We have suddenly started running into errors when attempting to publish to a MDS entity, both from the Excel add-in and the Web application.

When trying to add a member using the web app we encounter the error "2601: cannot insert duplicate key row in object 'mdm.tbl_2_30_EN' with unique index 'ux_tbl_2_30_EN_Version_ID_Code'. The duplicate key value is (2, 106229)."

I have queried the table mdm.tbl_2_30_EN and it seems that ID 106229 would be the next key created.  It does not exist yet, so I do not know why this error is occurring.

Has anybody ran into this problem using MDS before?  Why would this entity suddenly become corrupted somehow?

Any ideas would be appreciated.

Thanks.