This is required by 3.4.2 of the JPA specification (2.1 that I'm looking at):

"All non-relationship fields and properties and all relationships owned by the entity are included in version checks[35]."

and

"[35] This includes owned relationships maintained in join tables."

If you want to avoid this, switch the owning side of the relationship so Workers (which doesn't have optimistic locking) owns it.

Alternatively, you'll need to use native Hibernate API to bypass versions: https://stackoverflow.com/questions/33972564/is-it-possible-to-turn-off-hibernate-version-increment-for-particular-update#:~:text=Hibernate%20Optimistic%20Locking%20can%20be%20bypassed%20using%20hibernate,%2F%2FDetaching%20to%20prevent%20hibernate%20to%20spot%20dirty%20fields.