The lock is preventing users from changing the ore selection on the excavator. One user reported they couldn't change the ore selection mid-run and another user said they changed it, but it still showed the original selection.

Unable to reproduce this.  can change resource on the fly
Only the owner/team members can change the resource of a locked excavator.
other player can still see the UI to chenge resource, but will get a message in chat saying it did not work

hmm, ok i will keep an eye on it and test some more, thanks!