Sigh yes this is a well recognized risk which even the FDA has guidelines for: "The administration of a DNA vaccine exposes the patient to foreign DNA or its fragments that could be inserted into the host’s chromosomal DNA [70]. In the case of incorporation into an exon, an insertional mutation or a frameshift mutation occurs. Such mutations can cause a gene to malfunction or inactivate (i.e., a tumor suppressor gene). The insertion of foreign genes into the host genome could also lead to constituent expression of previously silent bacterial/parasite genes that have been inserted."(1)

To date, there is no licensed DNA vaccine for use in humans, which is my whole point we aren't testing for this and instead just using the whole US population as test subjects without informing them of the risk.

(1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105045/